diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index c42402a2..ad593115 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -31,6 +31,9 @@ Release Notes ⋮
     * Use ⚓️ and 📁 icons consistently in the UI to refer to 
       Root URLs and Groups respectively.
 
+* Workflow improvements
+    * Can now edit the name and source of Root URLs and Groups after creation.
+
 * Serving improvements
     * XML files like Atom feeds and RSS feeds are now served correctly,
       without introducing an invalid `<script>` tag.
diff --git a/src/crystal/browser/__init__.py b/src/crystal/browser/__init__.py
index 8d7d59f3..31c916ed 100644
--- a/src/crystal/browser/__init__.py
+++ b/src/crystal/browser/__init__.py
@@ -31,6 +31,7 @@
 from crystal.util.xthreading import (
     bg_call_later, fg_affinity, fg_call_later, fg_call_and_wait, set_is_quitting
 )
+from functools import partial
 import os
 import time
 from typing import ContextManager, Iterator, Optional
@@ -195,17 +196,23 @@ def _create_actions(self) -> None:
         self._new_root_url_action = Action(wx.ID_ANY,
             'New &Root URL...',
             wx.AcceleratorEntry(wx.ACCEL_CTRL, ord('R')),
-            self._on_add_url,
+            self._on_new_root_url,
             enabled=(not self._readonly),
             button_bitmap=TREE_NODE_ICONS()['entitytree_root_resource'],
             button_label='New &Root URL...')
         self._new_group_action = Action(wx.ID_ANY,
             'New &Group...',
             wx.AcceleratorEntry(wx.ACCEL_CTRL, ord('G')),
-            self._on_add_group,
+            self._on_new_group,
             enabled=(not self._readonly),
             button_bitmap=dict(DEFAULT_FOLDER_ICON_SET())[wx.TreeItemIcon_Normal],
             button_label='New &Group...')
+        self._edit_action = Action(wx.ID_ANY,
+            '&Edit...',
+            accel=wx.AcceleratorEntry(wx.ACCEL_NORMAL, wx.WXK_RETURN),
+            action_func=self._on_edit_entity,
+            enabled=False,
+            button_label=decorate_label('✏️', '&Edit...', ''))
         self._forget_action = Action(wx.ID_ANY,
             '&Forget',
             wx.AcceleratorEntry(wx.ACCEL_CTRL, wx.WXK_BACK),
@@ -218,14 +225,16 @@ def _create_actions(self) -> None:
             self._on_download_entity,
             enabled=False,
             button_label=decorate_label('⬇', '&Download', ''))
-        self._update_membership_action = Action(wx.ID_ANY,
-            'Update &Membership',
+        self._update_members_action = Action(wx.ID_ANY,
+            'Update &Members',
             accel=None,
-            action_func=self._on_update_group_membership,
+            action_func=self._on_update_group_members,
             enabled=False,
-            button_label=decorate_label('🔎', 'Update &Membership', ' '))
+            button_label=decorate_label('🔎', 'Update &Members', ' '))
         self._view_action = Action(wx.ID_ANY,
             '&View',
+            # TODO: Consider adding Space as a alternate accelerator
+            #wx.AcceleratorEntry(wx.ACCEL_NORMAL, wx.WXK_SPACE),
             wx.AcceleratorEntry(wx.ACCEL_CTRL|wx.ACCEL_SHIFT, ord('O')),
             self._on_view_entity,
             enabled=False,
@@ -271,10 +280,11 @@ def _create_menu_bar(self, raw_frame: wx.Frame) -> wx.MenuBar:
         entity_menu = wx.Menu()
         self._new_root_url_action.append_menuitem_to(entity_menu)
         self._new_group_action.append_menuitem_to(entity_menu)
+        self._edit_action.append_menuitem_to(entity_menu)
         self._forget_action.append_menuitem_to(entity_menu)
         entity_menu.AppendSeparator()
         self._download_action.append_menuitem_to(entity_menu)
-        self._update_membership_action.append_menuitem_to(entity_menu)
+        self._update_members_action.append_menuitem_to(entity_menu)
         self._view_action.append_menuitem_to(entity_menu)
         
         menubar = wx.MenuBar()
@@ -329,30 +339,29 @@ def _create_entity_tree(self, parent: wx.Window, progress_listener: OpenProjectP
     def _create_button_bar(self, parent: wx.Window):
         readonly = self._readonly  # cache
         
-        add_url_button = self._new_root_url_action.create_button(parent, name='cr-add-url-button')
-        
-        add_group_button = self._new_group_action.create_button(parent, name='cr-add-group-button')
-        
-        remove_entity_button = self._forget_action.create_button(parent, name='cr-forget-button')
-        
+        new_root_url_button = self._new_root_url_action.create_button(parent, name='cr-add-url-button')
+        new_group_button = self._new_group_action.create_button(parent, name='cr-add-group-button')
+        edit_entity_button = self._edit_action.create_button(parent, name='cr-edit-button')
+        forget_entity_button = self._forget_action.create_button(parent, name='cr-forget-button')
         download_button = self._download_action.create_button(parent, name='cr-download-button')
-        
-        update_membership_button = self._update_membership_action.create_button(
-            parent, name='cr-update-membership-button')
+        update_members_button = self._update_members_action.create_button(
+            parent, name='cr-update-members-button')
         
         view_button = self._view_action.create_button(parent, name='cr-view-button')
         
         content_sizer = wx.BoxSizer(wx.HORIZONTAL)
-        content_sizer.Add(add_url_button)
+        content_sizer.Add(new_root_url_button)
+        content_sizer.AddSpacer(_WINDOW_INNER_PADDING)
+        content_sizer.Add(new_group_button)
         content_sizer.AddSpacer(_WINDOW_INNER_PADDING)
-        content_sizer.Add(add_group_button)
+        content_sizer.Add(edit_entity_button)
         content_sizer.AddSpacer(_WINDOW_INNER_PADDING)
-        content_sizer.Add(remove_entity_button)
+        content_sizer.Add(forget_entity_button)
         content_sizer.AddSpacer(_WINDOW_INNER_PADDING * 2)
         content_sizer.AddStretchSpacer()
         content_sizer.Add(download_button)
         content_sizer.AddSpacer(_WINDOW_INNER_PADDING)
-        content_sizer.Add(update_membership_button)
+        content_sizer.Add(update_members_button)
         content_sizer.AddSpacer(_WINDOW_INNER_PADDING)
         content_sizer.Add(view_button)
         return content_sizer
@@ -430,25 +439,26 @@ def _on_close_frame(self, event: wx.CloseEvent) -> None:
         
         event.Skip()  # continue dispose of frame
     
-    # === Entity Pane: Events ===
+    # === Entity Pane: New/Edit Root Url ===
     
-    def _on_add_url(self, event: wx.CommandEvent) -> None:
-        def root_url_exists(url: str) -> bool:
-            r = self.project.get_resource(url)
-            if r is None:
-                return False
-            rr = self.project.get_root_resource(r)
-            return rr is not None
-            
+    def _on_new_root_url(self, event: wx.CommandEvent) -> None:
         NewRootUrlDialog(
-            self._frame, self._on_add_url_dialog_ok,
-            url_exists_func=root_url_exists,
+            self._frame,
+            self._on_new_root_url_dialog_ok,
+            url_exists_func=self._root_url_exists,
             initial_url=self._suggested_url_or_url_pattern_for_selection or '',
             initial_name=self._suggested_name_for_selection or '',
         )
     
+    def _root_url_exists(self, url: str) -> bool:
+        r = self.project.get_resource(url)
+        if r is None:
+            return False
+        rr = self.project.get_root_resource(r)
+        return rr is not None
+    
     @fg_affinity
-    def _on_add_url_dialog_ok(self, name: str, url: str) -> None:
+    def _on_new_root_url_dialog_ok(self, name: str, url: str) -> None:
         if url == '':
             raise ValueError('Invalid blank URL')
         try:
@@ -456,30 +466,103 @@ def _on_add_url_dialog_ok(self, name: str, url: str) -> None:
         except RootResource.AlreadyExists:
             raise ValueError('Invalid duplicate URL')
     
-    def _on_add_group(self, event: wx.CommandEvent) -> None:
+    @fg_affinity
+    def _on_edit_root_url_dialog_ok(self, rr: RootResource, name: str, url: str) -> None:
+        if url != rr.url:
+            raise ValueError()
+        rr.name = name
+        
+        # TODO: This update should happen in response to an event
+        #       fired by the entity itself.
+        self.entity_tree.root.update_title_of_descendants()  # update names in titles
+    
+    # === Entity Pane: New/Edit Group ===
+    
+    def _on_new_group(self, event: wx.CommandEvent) -> None:
         try:
             NewGroupDialog(
-                self._frame, self._on_add_group_dialog_ok,
+                self._frame,
+                self._on_new_group_dialog_ok,
                 self.project,
+                saving_source_would_create_cycle_func=lambda source: False,
                 initial_url_pattern=self._suggested_url_or_url_pattern_for_selection or '',
                 initial_source=self._suggested_source_for_selection,
                 initial_name=self._suggested_name_for_selection or '')
         except CancelLoadUrls:
             pass
     
-    def _on_add_group_dialog_ok(self, name: str, url_pattern: str, source):
+    @fg_affinity
+    def _on_new_group_dialog_ok(self, name: str, url_pattern: str, source: ResourceGroupSource) -> None:
         # TODO: Validate user input:
-        #       * Is name or url_pattern empty?
-        #       * Is name or url_pattern already taken?
-        rg = ResourceGroup(self.project, name, url_pattern, source)
+        #       * Is url_pattern empty?
+        #       * Is url_pattern already taken?
+        ResourceGroup(self.project, name, url_pattern, source)
     
-    def _on_forget_entity(self, event):
+    @fg_affinity
+    def _on_edit_group_dialog_ok(self, rg: ResourceGroup, name: str, url_pattern: str, source: ResourceGroupSource) -> None:
+        if url_pattern != rg.url_pattern:
+            raise ValueError()
+        (rg.name, rg.source) = (name, source)
+        
+        # TODO: This update should happen in response to an event
+        #       fired by the entity itself.
+        self.entity_tree.root.update_title_of_descendants()  # update names in titles
+    
+    def _saving_source_would_create_cycle(self, rg: ResourceGroup, source: ResourceGroupSource) -> bool:
+        ancestor_source = source  # type: ResourceGroupSource
+        while ancestor_source is not None:
+            if ancestor_source == rg:
+                return True
+            if isinstance(ancestor_source, ResourceGroup):
+                ancestor_source = ancestor_source.source  # reinterpret
+            else:
+                ancestor_source = None
+        return False
+    
+    # === Entity Pane: Other Commands ===
+    
+    def _on_edit_entity(self, event) -> None:
         selected_entity_pair = self.entity_tree.selected_entity_pair
         selected_or_related_entity = selected_entity_pair[0] or selected_entity_pair[1]
+        assert selected_or_related_entity is not None
+        
+        if isinstance(selected_or_related_entity, RootResource):
+            rr = selected_or_related_entity
+            NewRootUrlDialog(
+                self._frame,
+                partial(self._on_edit_root_url_dialog_ok, rr),
+                url_exists_func=self._root_url_exists,
+                initial_url=rr.url,
+                initial_name=rr.name,
+                is_edit=True,
+            )
+        elif isinstance(selected_or_related_entity, ResourceGroup):
+            rg = selected_or_related_entity
+            try:
+                NewGroupDialog(
+                    self._frame,
+                    partial(self._on_edit_group_dialog_ok, rg),
+                    self.project,
+                    saving_source_would_create_cycle_func=
+                        partial(self._saving_source_would_create_cycle, rg),
+                    initial_url_pattern=rg.url_pattern,
+                    initial_source=rg.source,
+                    initial_name=rg.name,
+                    is_edit=True)
+            except CancelLoadUrls:
+                pass
+        else:
+            raise AssertionError()
+    
+    def _on_forget_entity(self, event) -> None:
+        selected_entity_pair = self.entity_tree.selected_entity_pair
+        selected_or_related_entity = selected_entity_pair[0] or selected_entity_pair[1]
+        assert selected_or_related_entity is not None
         
         selected_or_related_entity.delete()
-        # TODO: This update() should happen in response to a delete
-        #       event fired by the entity itself.
+        
+        # TODO: This update() should happen in response to an event
+        #       fired by the entity itself.
         self.entity_tree.update()
     
     def _on_download_entity(self, event) -> None:
@@ -545,9 +628,9 @@ def fg_task() -> None:
                 fg_call_and_wait(fg_task)
         bg_call_later(bg_task)
     
-    def _on_update_group_membership(self, event):
+    def _on_update_group_members(self, event):
         selected_entity = self.entity_tree.selected_entity
-        selected_entity.update_membership()
+        selected_entity.update_members()
     
     def _on_view_entity(self, event) -> None:
         # TODO: If the server couldn't be started (ex: due to the default port being in
@@ -605,19 +688,24 @@ def start_server(self) -> 'ProjectServer':
         
         return self._project_server
     
+    # === Entity Pane: Events ===
+    
     def _on_selected_entity_changed(self, event: wx.TreeEvent) -> None:
         selected_entity_pair = self.entity_tree.selected_entity_pair  # cache
         selected_entity = selected_entity_pair[0]
         selected_or_related_entity = selected_entity_pair[0] or selected_entity_pair[1]
         
         readonly = self._readonly  # cache
+        self._edit_action.enabled = (
+            (not readonly) and
+            isinstance(selected_or_related_entity, (ResourceGroup, RootResource)))
         self._forget_action.enabled = (
             (not readonly) and
             isinstance(selected_or_related_entity, (ResourceGroup, RootResource)))
         self._download_action.enabled = (
             (not readonly) and
             selected_entity is not None)
-        self._update_membership_action.enabled = (
+        self._update_members_action.enabled = (
             (not readonly) and
             isinstance(selected_entity, ResourceGroup))
         self._view_action.enabled = (
diff --git a/src/crystal/browser/entitytree.py b/src/crystal/browser/entitytree.py
index 81b8efd3..9a4e9729 100644
--- a/src/crystal/browser/entitytree.py
+++ b/src/crystal/browser/entitytree.py
@@ -832,8 +832,10 @@ def entity(self) -> RootResource:
     # === Comparison ===
     
     def __eq__(self, other):
-        return isinstance(other, RootResourceNode) and (
-            self.root_resource == other.root_resource)
+        return (
+            isinstance(other, RootResourceNode) and
+            self.root_resource == other.root_resource
+        )
     def __hash__(self):
         return hash(self.root_resource)
 
@@ -1090,8 +1092,10 @@ def on_more_expanded(self, more_node: MorePlaceholderNode) -> None:
     # === Comparison ===
     
     def __eq__(self, other) -> bool:
-        return isinstance(other, ResourceGroupNode) and (
-            self.resource_group == other.resource_group)
+        return (
+            isinstance(other, ResourceGroupNode) and
+            self.resource_group == other.resource_group
+        )
     def __hash__(self) -> int:
         return hash(self.resource_group)
 
diff --git a/src/crystal/browser/new_group.py b/src/crystal/browser/new_group.py
index 5f9dc9d7..4ee6c6b7 100644
--- a/src/crystal/browser/new_group.py
+++ b/src/crystal/browser/new_group.py
@@ -5,7 +5,9 @@
 from crystal.progress import CancelLoadUrls
 from crystal.util.unicode_labels import decorate_label
 from crystal.util.wx_bind import bind
-from crystal.util.wx_dialog import position_dialog_initially
+from crystal.util.wx_dialog import (
+    CreateButtonSizer, position_dialog_initially, ShowModal,
+)
 from crystal.util.wx_static_box_sizer import wrap_static_box_sizer_child
 from crystal.util.xos import is_linux
 import sys
@@ -28,9 +30,11 @@ def __init__(self,
             parent: wx.Window,
             on_finish: Callable[[str, str, ResourceGroupSource], None],
             project: Project,
+            saving_source_would_create_cycle_func: Callable[[ResourceGroupSource], bool],
             initial_url_pattern: str='',
             initial_source: ResourceGroupSource=None,
             initial_name: str='',
+            is_edit: bool=False,
             ) -> None:
         """
         Arguments:
@@ -46,6 +50,7 @@ def __init__(self,
         """
         self._project = project
         self._on_finish = on_finish
+        self._saving_source_would_create_cycle_func = saving_source_would_create_cycle_func
         
         # Show progress dialog in advance if will need to load all project URLs
         try:
@@ -54,7 +59,8 @@ def __init__(self,
             raise
         
         dialog = self.dialog = wx.Dialog(
-            parent, title='New Group',
+            parent,
+            title=('New Group' if not is_edit else 'Edit Group'),
             name='cr-new-group-dialog',
             style=wx.DEFAULT_DIALOG_STYLE|wx.RESIZE_BORDER)
         dialog_sizer = wx.BoxSizer(wx.VERTICAL)
@@ -96,17 +102,22 @@ def __init__(self,
         
         content_sizer = wx.BoxSizer(wx.VERTICAL)
         content_sizer.Add(
-            self._create_fields(dialog, initial_url_pattern, initial_source, initial_name),
+            self._create_fields(dialog, initial_url_pattern, initial_source, initial_name, is_edit),
             flag=wx.EXPAND)
         content_sizer.Add(preview_box, proportion=1, flag=wx.EXPAND|preview_box_flags, border=preview_box_border)
         
+        ok_button_id = (wx.ID_NEW if not is_edit else wx.ID_SAVE)
         dialog_sizer.Add(content_sizer, proportion=1, flag=wx.EXPAND|wx.ALL,
             border=_WINDOW_INNER_PADDING)
-        dialog_sizer.Add(dialog.CreateButtonSizer(wx.OK|wx.CANCEL), flag=wx.EXPAND|wx.BOTTOM,
+        dialog_sizer.Add(CreateButtonSizer(dialog, ok_button_id, wx.ID_CANCEL), flag=wx.EXPAND|wx.BOTTOM,
             border=_WINDOW_INNER_PADDING)
         
         if not fields_hide_hint_when_focused():
-            self.pattern_field.SetFocus()  # initialize focus
+            # Initialize focus
+            if not is_edit:
+                self.pattern_field.SetFocus()
+            else:
+                self.name_field.SetFocus()
         self._update_preview_urls()
         
         position_dialog_initially(dialog)
@@ -121,6 +132,7 @@ def _create_fields(self,
             initial_url_pattern: str,
             initial_source: ResourceGroupSource,
             initial_name: str,
+            is_edit: bool,
             ) -> wx.Sizer:
         fields_sizer = wx.FlexGridSizer(cols=2,
             vgap=_FORM_ROW_SPACING, hgap=_FORM_LABEL_INPUT_SPACING)
@@ -134,6 +146,7 @@ def _create_fields(self,
         bind(self.pattern_field, wx.EVT_TEXT, self._on_pattern_field_changed)
         self.pattern_field.Hint = 'https://example.com/post/*'
         self.pattern_field.SetSelection(-1, -1)  # select all upon focus
+        self.pattern_field.Enabled = not is_edit
         pattern_field_sizer.Add(self.pattern_field, flag=wx.EXPAND)
         pattern_field_sizer.Add(wx.StaticText(parent, label='# = digit, @ = alpha, * = any nonslash, ** = any'), flag=wx.EXPAND)
         
@@ -227,7 +240,7 @@ def _on_pattern_field_changed(self, event) -> None:
     
     def _on_button(self, event: wx.CommandEvent) -> None:
         btn_id = event.GetEventObject().GetId()
-        if btn_id == wx.ID_OK:
+        if btn_id in (wx.ID_NEW, wx.ID_SAVE):
             self._on_ok(event)
         elif btn_id == wx.ID_CANCEL:
             self._on_cancel(event)
@@ -240,7 +253,20 @@ def _on_ok(self, event: wx.CommandEvent) -> None:
         url_pattern = self.pattern_field.GetValue()
         source = self.source_choice_box.GetClientData(
             self.source_choice_box.GetSelection())
+        if self._saving_source_would_create_cycle_func(source):
+            dialog = wx.MessageDialog(
+                self.dialog,
+                message='Cannot use that Source because it has this group as a Source.',
+                caption='Source Cycle Created',
+                style=wx.OK,
+            )
+            dialog.Name = 'cr-source-cycle-created'
+            position_dialog_initially(dialog)
+            choice = ShowModal(dialog)
+            assert wx.ID_OK == choice
+            return
         self._on_finish(name, url_pattern, source)
+        
         self.dialog.Destroy()
     
     def _on_cancel(self, event: wx.CommandEvent) -> None:
diff --git a/src/crystal/browser/new_root_url.py b/src/crystal/browser/new_root_url.py
index e39ff6a5..2ec762f3 100644
--- a/src/crystal/browser/new_root_url.py
+++ b/src/crystal/browser/new_root_url.py
@@ -1,6 +1,8 @@
 from crystal.url_input import UrlCleaner
 from crystal.util.wx_bind import bind
-from crystal.util.wx_dialog import position_dialog_initially, ShowModal
+from crystal.util.wx_dialog import (
+    CreateButtonSizer, position_dialog_initially, ShowModal,
+)
 from crystal.util.xos import is_wx_gtk
 from crystal.util.xthreading import fg_affinity, fg_call_later
 import os
@@ -20,6 +22,9 @@ class NewRootUrlDialog:
     # NOTE: Only changed when tests are running
     _last_opened: 'Optional[NewRootUrlDialog]'=None
     
+    url_field: wx.TextCtrl
+    name_field: wx.TextCtrl
+    
     # === Init ===
     
     def __init__(self,
@@ -28,6 +33,7 @@ def __init__(self,
             url_exists_func: Callable[[str], bool],
             initial_url: str='',
             initial_name: str='',
+            is_edit: bool=False,
             ) -> None:
         """
         Arguments:
@@ -37,6 +43,7 @@ def __init__(self,
         """
         self._on_finish = on_finish
         self._url_exists_func = url_exists_func
+        self._is_edit = is_edit
         
         self._url_field_focused = False
         self._last_cleaned_url = None  # type: Optional[str]
@@ -45,7 +52,9 @@ def __init__(self,
         self._is_destroying_or_destroyed = False
         
         dialog = self.dialog = wx.Dialog(
-            parent, title='New Root URL', name='cr-new-root-url-dialog',
+            parent,
+            title=('New Root URL' if not is_edit else 'Edit Root URL'),
+            name='cr-new-root-url-dialog',
             style=wx.DEFAULT_DIALOG_STYLE|wx.RESIZE_BORDER)
         dialog_sizer = wx.BoxSizer(wx.VERTICAL)
         dialog.SetSizer(dialog_sizer)
@@ -53,17 +62,22 @@ def __init__(self,
         bind(dialog, wx.EVT_CLOSE, self._on_close)
         bind(dialog, wx.EVT_WINDOW_DESTROY, self._on_destroyed)
         
-        dialog_sizer.Add(self._create_fields(dialog, initial_url, initial_name), flag=wx.EXPAND|wx.ALL,
+        ok_button_id = (wx.ID_NEW if not is_edit else wx.ID_SAVE)
+        dialog_sizer.Add(self._create_fields(dialog, initial_url, initial_name, is_edit), flag=wx.EXPAND|wx.ALL,
             border=_WINDOW_INNER_PADDING)
-        dialog_sizer.Add(dialog.CreateButtonSizer(wx.OK|wx.CANCEL), flag=wx.EXPAND|wx.BOTTOM,
+        dialog_sizer.Add(CreateButtonSizer(dialog, ok_button_id, wx.ID_CANCEL), flag=wx.EXPAND|wx.BOTTOM,
             border=_WINDOW_INNER_PADDING)
-        self.ok_button = dialog.FindWindow(id=wx.ID_OK)
+        self.ok_button = dialog.FindWindow(id=ok_button_id)
         self.cancel_button = dialog.FindWindow(id=wx.ID_CANCEL)
         
         self._update_ok_enabled()
         
         if not fields_hide_hint_when_focused():
-            self.url_field.SetFocus()  # initialize focus
+            # Initialize focus
+            if not is_edit:
+                self.url_field.SetFocus()
+            else:
+                self.name_field.SetFocus()
         
         position_dialog_initially(dialog)
         dialog.Show(True)
@@ -76,7 +90,7 @@ def __init__(self,
         if os.environ.get('CRYSTAL_RUNNING_TESTS', 'False') == 'True':
             NewRootUrlDialog._last_opened = self
     
-    def _create_fields(self, parent: wx.Window, initial_url: str, initial_name: str) -> wx.Sizer:
+    def _create_fields(self, parent: wx.Window, initial_url: str, initial_name: str, is_edit: bool) -> wx.Sizer:
         fields_sizer = wx.FlexGridSizer(rows=2, cols=2,
             vgap=_FORM_ROW_SPACING, hgap=_FORM_LABEL_INPUT_SPACING)
         fields_sizer.AddGrowableCol(1)
@@ -94,6 +108,7 @@ def _create_fields(self, parent: wx.Window, initial_url: str, initial_name: str)
                     name='cr-new-root-url-dialog__url-field')
                 self.url_field.Hint = 'https://example.com/'
                 self.url_field.SetSelection(-1, -1)  # select all upon focus
+                self.url_field.Enabled = not is_edit
                 bind(self.url_field, wx.EVT_TEXT, self._update_ok_enabled)
                 bind(self.url_field, wx.EVT_SET_FOCUS, self._on_url_field_focus)
                 bind(self.url_field, wx.EVT_KILL_FOCUS, self._on_url_field_blur)
@@ -222,7 +237,7 @@ def _on_url_field_blur(self, event: Optional[wx.FocusEvent]=None) -> None:
     
     def _on_button(self, event: wx.CommandEvent) -> None:
         btn_id = event.GetEventObject().GetId()
-        if btn_id == wx.ID_OK:
+        if btn_id in (wx.ID_NEW, wx.ID_SAVE):
             self._on_ok(event)
         elif btn_id == wx.ID_CANCEL:
             self._on_cancel(event)
@@ -247,8 +262,9 @@ def _on_ok(self, event: Optional[wx.CommandEvent]=None) -> None:
         
         name = self.name_field.Value
         url = self.url_field.Value
-        if self._url_exists_func(url):
-            dialog = wx.MessageDialog(None,
+        if not self._is_edit and self._url_exists_func(url):
+            dialog = wx.MessageDialog(
+                self.dialog,
                 message='That root URL already exists in the project.',
                 caption='Root URL Exists',
                 style=wx.OK,
@@ -263,7 +279,6 @@ def _on_ok(self, event: Optional[wx.CommandEvent]=None) -> None:
             self.ok_button.Enabled = True
             assert self.cancel_button.Enabled == True
             return
-        
         self._on_finish(name, url)
         
         self._destroy()
diff --git a/src/crystal/model.py b/src/crystal/model.py
index 06990648..54d201ed 100644
--- a/src/crystal/model.py
+++ b/src/crystal/model.py
@@ -990,10 +990,8 @@ def _set_min_fetch_date(self, min_fetch_date: Optional[datetime.datetime]) -> No
             for lis in self.listeners:
                 if hasattr(lis, 'min_fetch_date_did_change'):
                     lis.min_fetch_date_did_change()  # type: ignore[attr-defined]
-    min_fetch_date = property(
-        _get_min_fetch_date,
-        _set_min_fetch_date,
-        doc="""
+    min_fetch_date = property(_get_min_fetch_date, _set_min_fetch_date, doc=
+        """
         If non-None then any resource fetched <= this datetime
         will be considered stale and subject to being redownloaded.
         
@@ -2102,8 +2100,8 @@ class RootResource:
     Persisted and auto-saved.
     """
     project: Project
-    name: str
-    resource: Resource
+    _name: str
+    _resource: Resource
     _id: int  # or None if deleted
     
     # === Init ===
@@ -2132,8 +2130,8 @@ def __new__(cls, project: Project, name: str, resource: Resource, _id: Optional[
         else:
             self = object.__new__(cls)
             self.project = project
-            self.name = name
-            self.resource = resource
+            self._name = name
+            self._resource = resource
             
             if project._loading:
                 assert _id is not None
@@ -2174,11 +2172,33 @@ def delete(self) -> None:
     
     # === Properties ===
     
+    def _get_name(self) -> str:
+        """Name of this root resource. Possibly ''."""
+        return self._name
+    def _set_name(self, name: str) -> None:
+        if self._name == name:
+            return
+        
+        if self.project.readonly:
+            raise ProjectReadOnlyError()
+        c = self.project._db.cursor()
+        c.execute('update root_resource set name=? where id=?', (
+            name,
+            self._id,))
+        self.project._db.commit()
+        
+        self._name = name
+    name = cast(str, property(_get_name, _set_name))
+    
     @property
     def display_name(self) -> str:
-        """Name of this root resource that is used in the UI."""
+        """Name of this root resource that is used in the UI. Never ''."""
         return self.name or self.url
     
+    @property
+    def resource(self) -> Resource:
+        return self._resource
+    
     @property
     def url(self) -> str:
         return self.resource.url
@@ -3137,7 +3157,7 @@ def __init__(self,
             raise ValueError('Cannot create group with empty pattern')
         
         self.project = project
-        self.name = name
+        self._name = name
         self.url_pattern = url_pattern
         self._url_pattern_re = ResourceGroup.create_re_for_url_pattern(url_pattern)
         self._source = None  # type: Union[ResourceGroupSource, EllipsisType]
@@ -3198,6 +3218,24 @@ def delete(self) -> None:
     
     # === Properties ===
     
+    def _get_name(self) -> str:
+        """Name of this resource group. Possibly ''."""
+        return self._name
+    def _set_name(self, name: str) -> None:
+        if self._name == name:
+            return
+        
+        if self.project.readonly:
+            raise ProjectReadOnlyError()
+        c = self.project._db.cursor()
+        c.execute('update resource_group set name=? where id=?', (
+            name,
+            self._id,))
+        self.project._db.commit()
+        
+        self._name = name
+    name = cast(str, property(_get_name, _set_name))
+    
     @property
     def display_name(self) -> str:
         """Name of this group that is used in the UI."""
@@ -3215,6 +3253,9 @@ def _get_source(self) -> ResourceGroupSource:
             raise ValueError('Expected ResourceGroup.init_source() to have been already called')
         return self._source
     def _set_source(self, value: ResourceGroupSource) -> None:
+        if value == self._source:
+            return
+        
         if value is None:
             source_type = None
             source_id = None
@@ -3364,7 +3405,7 @@ def create_download_task(self, *, needs_result: bool=False) -> DownloadResourceG
         from crystal.task import DownloadResourceGroupTask
         return DownloadResourceGroupTask(self)
     
-    def update_membership(self) -> None:
+    def update_members(self) -> None:
         """
         Updates the membership of this group asynchronously.
         
diff --git a/src/crystal/tests/test_edit_group.py b/src/crystal/tests/test_edit_group.py
new file mode 100644
index 00000000..75784997
--- /dev/null
+++ b/src/crystal/tests/test_edit_group.py
@@ -0,0 +1,226 @@
+from crystal.model import Project, ResourceGroup
+from crystal.tests.util.controls import click_button, TreeItem
+from crystal.tests.util.server import extracted_project
+from crystal.tests.util.wait import (
+    first_child_of_tree_item_is_not_loading_condition,
+    is_enabled_condition,
+    wait_for,
+)
+from crystal.tests.util.windows import NewGroupDialog, OpenOrCreateDialog
+from crystal.util.xos import is_windows
+from unittest import skip
+from unittest.mock import patch
+import wx
+
+
+async def test_can_edit_name_of_group() -> None:
+    with extracted_project('testdata_xkcd.crystalproj.zip') as project_dirpath:
+        comic_pattern = 'https://xkcd.com/#/'
+        
+        async with (await OpenOrCreateDialog.wait_for()).open(project_dirpath) as mw:
+            root_ti = TreeItem.GetRootItem(mw.entity_tree.window)
+            
+            home_ti = root_ti.GetFirstChild()
+            assert home_ti is not None
+            assert home_ti.Text.endswith('Home')
+            
+            home_ti.Expand()
+            await wait_for(first_child_of_tree_item_is_not_loading_condition(home_ti))
+            (home_ti__comic_ti,) = [
+                child for child in home_ti.Children
+                if child.Text.startswith(f'{comic_pattern} - ')
+            ]
+            assert home_ti__comic_ti.Text.endswith('Comics')
+            
+            (comic_ti,) = [
+                child for child in root_ti.Children
+                if child.Text.startswith(f'{comic_pattern} - ')
+            ]
+            assert comic_ti.Text.endswith('Comics')
+            
+            # Ensure can rename top-level ResourceGroupNode
+            if True:
+                comic_ti.SelectItem()
+                
+                assert mw.edit_button.Enabled
+                click_button(mw.edit_button)
+                ngd = await NewGroupDialog.wait_for()
+                
+                # 1. Ensure prepopulates correct information
+                # 2. Test: Cannot edit URL pattern
+                assert comic_pattern == ngd.pattern_field.Value
+                assert 'Comics' == ngd.name_field.Value
+                assert 'Home' == ngd.source
+                assert not ngd.pattern_field.Enabled
+                assert ngd.name_field.HasFocus  # default focused field
+                
+                ngd.name_field.Value = 'Comics2'
+                await ngd.ok()
+                (comic_ti,) = [
+                    child for child in root_ti.Children
+                    if child.Text.startswith(f'{comic_pattern} - ')
+                ]
+                assert comic_ti.Text.endswith('Comics2')
+                
+                # Ensure selection did not change
+                assert comic_ti.IsSelected()
+                
+                # Ensure all copies of comic node have updated name
+                assert home_ti.IsExpanded()
+                (home_ti__comic_ti,) = [
+                    child for child in home_ti.Children
+                    if child.Text.startswith(f'{comic_pattern} - ')
+                ]
+                assert home_ti__comic_ti.Text.endswith('Comics2')
+            
+            # Ensure can rename nested GroupedLinkedResourcesNode
+            if True:
+                home_ti__comic_ti.SelectItem()
+                
+                if is_windows():
+                    await wait_for(is_enabled_condition(mw.edit_button), timeout=.5)
+                assert mw.edit_button.Enabled
+                click_button(mw.edit_button)
+                ngd = await NewGroupDialog.wait_for()
+                
+                # Ensure prepopulates correct information
+                assert comic_pattern == ngd.pattern_field.Value
+                assert 'Comics2' == ngd.name_field.Value
+                
+                ngd.name_field.Value = 'Comics'
+                await ngd.ok()
+                home_ti = root_ti.GetFirstChild()
+                assert home_ti is not None
+                
+                # Ensure selection did not change
+                assert home_ti.IsExpanded()
+                (home_ti__comic_ti,) = [
+                    child for child in home_ti.Children
+                    if child.Text.startswith(f'{comic_pattern} - ')
+                ]
+                assert home_ti__comic_ti.IsSelected()
+                
+                # Ensure all copies of home node have updated name
+                (comic_ti,) = [
+                    child for child in root_ti.Children
+                    if child.Text.startswith(f'{comic_pattern} - ')
+                ]
+                assert comic_ti.Text.endswith('Comics')
+                assert home_ti__comic_ti.Text.endswith('Comics')
+
+
+async def test_can_edit_source_of_group() -> None:
+    with extracted_project('testdata_xkcd.crystalproj.zip') as project_dirpath:
+        comic_pattern = 'https://xkcd.com/#/'
+        first_comic_pattern = 'https://xkcd.com/1/'
+        
+        async with (await OpenOrCreateDialog.wait_for()).open(project_dirpath) as mw:
+            project = Project._last_opened_project
+            assert project is not None
+            
+            root_ti = TreeItem.GetRootItem(mw.entity_tree.window)
+            (comic_ti,) = [
+                child for child in root_ti.Children
+                if child.Text.startswith(f'{comic_pattern} - ')
+            ]
+            comic_ti.SelectItem()
+            
+            # Ensure can edit source to be root resource
+            if True:
+                assert comic_ti.IsSelected()
+                
+                assert mw.edit_button.Enabled
+                click_button(mw.edit_button)
+                ngd = await NewGroupDialog.wait_for()
+                assert 'Home' == ngd.source
+                
+                ngd.source = 'Atom Feed'
+                await ngd.ok()
+                
+                click_button(mw.edit_button)
+                ngd = await NewGroupDialog.wait_for()
+                assert 'Atom Feed' == ngd.source
+                await ngd.ok()
+            
+            # Ensure can edit source to be group
+            if True:
+                ResourceGroup(project, 'First Comic', first_comic_pattern)
+                (first_comic_ti,) = [
+                    child for child in root_ti.Children
+                    if child.Text.startswith(f'{first_comic_pattern} - ')
+                ]
+                
+                assert comic_ti.IsSelected()
+                
+                assert mw.edit_button.Enabled
+                click_button(mw.edit_button)
+                ngd = await NewGroupDialog.wait_for()
+                assert 'Atom Feed' == ngd.source
+                
+                ngd.source = 'First Comic'
+                await ngd.ok()
+                
+                click_button(mw.edit_button)
+                ngd = await NewGroupDialog.wait_for()
+                assert 'First Comic' == ngd.source
+                await ngd.ok()
+            
+            did_respond_to_source_cycle_created_model = False
+            def click_ok_in_source_cycle_created_model(dialog: wx.Dialog) -> int:
+                assert 'cr-source-cycle-created' == dialog.Name
+                
+                nonlocal did_respond_to_source_cycle_created_model
+                did_respond_to_source_cycle_created_model = True
+                
+                return wx.ID_OK
+            
+            # Ensure cannot edit source to be self
+            if True:
+                assert comic_ti.IsSelected()
+                
+                assert mw.edit_button.Enabled
+                click_button(mw.edit_button)
+                ngd = await NewGroupDialog.wait_for()
+                assert 'First Comic' == ngd.source
+                
+                ngd.source = 'Comics'
+                
+                with patch('crystal.browser.new_group.ShowModal', click_ok_in_source_cycle_created_model):
+                    click_button(ngd.ok_button)
+                    assert did_respond_to_source_cycle_created_model
+                    did_respond_to_source_cycle_created_model = False  # reset
+                
+                await ngd.cancel()
+            
+            # Ensure cannot edit source to be group that would create cycle
+            if True:
+                first_comic_ti.SelectItem()
+                
+                assert mw.edit_button.Enabled
+                click_button(mw.edit_button)
+                ngd = await NewGroupDialog.wait_for()
+                assert None == ngd.source
+                
+                ngd.source = 'Comics'
+                
+                with patch('crystal.browser.new_group.ShowModal', click_ok_in_source_cycle_created_model):
+                    click_button(ngd.ok_button)
+                    assert did_respond_to_source_cycle_created_model
+                    did_respond_to_source_cycle_created_model = False  # reset
+                
+                await ngd.cancel()
+
+
+@skip('covered by: test_can_edit_name_of_group')
+async def test_cannot_edit_url_pattern_of_group() -> None:
+    pass
+
+
+@skip('covered by: test_can_edit_source_of_group')
+async def test_given_editing_group_when_select_self_as_source_and_press_save_then_shows_error_dialog() -> None:
+    pass
+
+
+@skip('covered by: test_can_edit_source_of_group')
+async def test_given_editing_group_when_select_source_that_would_create_cycle_and_press_save_then_shows_error_dialog() -> None:
+    pass
diff --git a/src/crystal/tests/test_edit_root_url.py b/src/crystal/tests/test_edit_root_url.py
new file mode 100644
index 00000000..52d92c20
--- /dev/null
+++ b/src/crystal/tests/test_edit_root_url.py
@@ -0,0 +1,110 @@
+from crystal.model import Project, ResourceGroup
+from crystal.tests.util.controls import click_button, TreeItem
+from crystal.tests.util.server import extracted_project
+from crystal.tests.util.wait import (
+    first_child_of_tree_item_is_not_loading_condition,
+    wait_for,
+)
+from crystal.tests.util.windows import NewRootUrlDialog, OpenOrCreateDialog
+from unittest import skip
+
+
+async def test_can_edit_name_of_root_url() -> None:
+    with extracted_project('testdata_xkcd.crystalproj.zip') as project_dirpath:
+        home_url = 'https://xkcd.com/'
+        home_g_pattern = 'https://xkcd.*/'
+        assert home_g_pattern != home_url
+        
+        async with (await OpenOrCreateDialog.wait_for()).open(project_dirpath) as mw:
+            project = Project._last_opened_project
+            assert project is not None
+            
+            ResourceGroup(project, 'Home Group', home_g_pattern)
+            
+            root_ti = TreeItem.GetRootItem(mw.entity_tree.window)
+            home_ti = root_ti.GetFirstChild()
+            assert home_ti is not None
+            assert home_ti.Text.endswith('Home')
+            
+            home_ti.Expand()
+            await wait_for(first_child_of_tree_item_is_not_loading_condition(home_ti))
+            (home_ti__home_ti,) = [
+                child for child in home_ti.Children
+                if child.Text.startswith(f'{home_url} - ')
+            ]
+            assert home_ti__home_ti.Text.endswith('Home')
+            
+            (home_g_ti,) = [
+                child for child in root_ti.Children
+                if child.Text.startswith(f'{home_g_pattern} - ')
+            ]
+            assert home_g_ti.Text.endswith('Home Group')
+            
+            home_g_ti.Expand()
+            await wait_for(first_child_of_tree_item_is_not_loading_condition(home_g_ti))
+            (home_g_ti__home_ti,) = [
+                child for child in home_g_ti.Children
+                if child.Text.startswith(f'{home_url} - ')
+            ]
+            assert home_g_ti__home_ti.Text.endswith('Home')
+            
+            # Ensure can rename top-level RootResourceNode
+            if True:
+                home_ti.SelectItem()
+                
+                assert mw.edit_button.Enabled
+                click_button(mw.edit_button)
+                nud = await NewRootUrlDialog.wait_for()
+                
+                # 1. Ensure prepopulates correct information
+                # 2. Test: Cannot edit URL
+                assert home_url == nud.url_field.Value
+                assert 'Home' == nud.name_field.Value
+                #assert None == ngd.source
+                assert not nud.url_field.Enabled
+                assert nud.name_field.HasFocus  # default focused field
+                
+                nud.name_field.Value = 'Home2'
+                await nud.ok()
+                home_ti = root_ti.GetFirstChild()
+                assert home_ti is not None
+                
+                # Ensure selection did not change
+                assert home_ti.IsSelected()
+                assert home_ti.IsExpanded()
+                
+                # Ensure all copies of home node have updated name
+                assert home_ti.Text.endswith('Home2')
+                assert home_ti__home_ti.Text.endswith('Home2')
+                assert home_g_ti__home_ti.Text.endswith('Home2')
+            
+            # Ensure can rename nested RootResourceNode
+            if True:
+                home_ti__home_ti.SelectItem()
+                
+                assert mw.edit_button.Enabled
+                click_button(mw.edit_button)
+                nud = await NewRootUrlDialog.wait_for()
+                
+                # Ensure prepopulates correct information
+                assert home_url == nud.url_field.Value
+                assert 'Home2' == nud.name_field.Value
+                
+                nud.name_field.Value = 'Home'
+                await nud.ok()
+                home_ti = root_ti.GetFirstChild()
+                assert home_ti is not None
+                
+                # Ensure selection did not change
+                assert home_ti.IsExpanded()
+                assert home_ti__home_ti.IsSelected()
+                
+                # Ensure all copies of home node have updated name
+                assert home_ti.Text.endswith('Home')
+                assert home_ti__home_ti.Text.endswith('Home')
+                assert home_g_ti__home_ti.Text.endswith('Home')
+
+
+@skip('covered by: test_can_edit_name_of_root_url')
+async def test_cannot_edit_url_of_root_url() -> None:
+    pass
diff --git a/src/crystal/tests/test_workflows.py b/src/crystal/tests/test_workflows.py
index f807a97c..35c71bd8 100644
--- a/src/crystal/tests/test_workflows.py
+++ b/src/crystal/tests/test_workflows.py
@@ -253,7 +253,7 @@ async def test_can_download_and_serve_a_static_site() -> None:
                     assert False == (await is_url_not_in_archive(atom_feed_url))
                     assert False == (await is_url_not_in_archive(rss_feed_url))
             
-                # Test can update membership of resource group, when other resource group is source
+                # Test can update members of resource group, when other resource group is source
                 if True:
                     # Undownload all members of the feed group
                     await _undownload_url([atom_feed_url, rss_feed_url], mw, project_dirpath)
@@ -280,7 +280,7 @@ async def test_can_download_and_serve_a_static_site() -> None:
                     # which should download members of feed group automatically
                     assert tree_has_no_children_condition(mw.task_tree)()
                     feed_item_group_ti.SelectItem()
-                    click_button(mw.update_membership_button)
+                    click_button(mw.update_members_button)
                     await wait_for_download_to_start_and_finish(mw.task_tree)
                 
                 # Ensure members of the feed group were downloaded
@@ -390,7 +390,7 @@ async def test_can_download_and_serve_a_static_site() -> None:
                 # Test cannot download/update/forget existing resource group in read-only project
                 feed_group_ti.SelectItem()
                 assert False == mw.download_button.IsEnabled()
-                assert False == mw.update_membership_button.IsEnabled()
+                assert False == mw.update_members_button.IsEnabled()
                 assert False == mw.forget_button.IsEnabled()
                 
                 # Start server
diff --git a/src/crystal/tests/util/wait.py b/src/crystal/tests/util/wait.py
index efbe6864..b29f5488 100644
--- a/src/crystal/tests/util/wait.py
+++ b/src/crystal/tests/util/wait.py
@@ -219,6 +219,12 @@ def tree_item_has_no_children() -> Optional[bool]:
     return tree_item_has_no_children
 
 
+def is_enabled_condition(window: wx.Window) -> Callable[[], Optional[bool]]:
+    def is_enabled() -> Optional[bool]:
+        return window.Enabled or None
+    return is_enabled
+
+
 def not_condition(condition: Callable[[], Optional[_T]]) -> Callable[[], Optional[bool]]:
     def not_() -> Optional[bool]:
         if condition():
diff --git a/src/crystal/tests/util/windows.py b/src/crystal/tests/util/windows.py
index 64924c00..3ad44c4c 100644
--- a/src/crystal/tests/util/windows.py
+++ b/src/crystal/tests/util/windows.py
@@ -152,9 +152,10 @@ class MainWindow:
     entity_tree: 'EntityTree'
     add_url_button: wx.Button
     add_group_button: wx.Button
+    edit_button: wx.Button
     forget_button: wx.Button
     download_button: wx.Button
-    update_membership_button: wx.Button
+    update_members_button: wx.Button
     view_button: wx.Button
     task_tree: wx.TreeCtrl
     preferences_button: wx.Button
@@ -180,12 +181,14 @@ async def _connect(self) -> None:
         assert isinstance(self.add_url_button, wx.Button)
         self.add_group_button = self.main_window.FindWindow(name='cr-add-group-button')
         assert isinstance(self.add_group_button, wx.Button)
+        self.edit_button = self.main_window.FindWindow(name='cr-edit-button')
+        assert isinstance(self.edit_button, wx.Button)
         self.forget_button = self.main_window.FindWindow(name='cr-forget-button')
         assert isinstance(self.forget_button, wx.Button)
         self.download_button = self.main_window.FindWindow(name='cr-download-button')
         assert isinstance(self.download_button, wx.Button)
-        self.update_membership_button = self.main_window.FindWindow(name='cr-update-membership-button')
-        assert isinstance(self.update_membership_button, wx.Button)
+        self.update_members_button = self.main_window.FindWindow(name='cr-update-members-button')
+        assert isinstance(self.update_members_button, wx.Button)
         self.view_button = self.main_window.FindWindow(name='cr-view-button')
         assert isinstance(self.view_button, wx.Button)
         self.task_tree = self.main_window.FindWindow(name='cr-task-tree')
@@ -332,7 +335,9 @@ async def wait_for() -> NewRootUrlDialog:
         assert isinstance(self.url_cleaner_spinner, wx.ActivityIndicator)
         self.name_field = self._dialog.FindWindow(name='cr-new-root-url-dialog__name-field')
         assert isinstance(self.name_field, wx.TextCtrl)
-        self.ok_button = self._dialog.FindWindow(id=wx.ID_OK)
+        self.ok_button = self._dialog.FindWindow(id=wx.ID_NEW)
+        if self.ok_button is None:
+            self.ok_button = self._dialog.FindWindow(id=wx.ID_SAVE)
         assert isinstance(self.ok_button, wx.Button)
         self.cancel_button = self._dialog.FindWindow(id=wx.ID_CANCEL)
         assert isinstance(self.cancel_button, wx.Button)
@@ -395,7 +400,9 @@ async def wait_for() -> NewGroupDialog:
         assert isinstance(self.preview_members_list, wx.ListBox)
         self.cancel_button = add_group_dialog.FindWindow(id=wx.ID_CANCEL)
         assert isinstance(self.cancel_button, wx.Button)
-        self.ok_button = add_group_dialog.FindWindow(id=wx.ID_OK)
+        self.ok_button = add_group_dialog.FindWindow(id=wx.ID_NEW)
+        if self.ok_button is None:
+            self.ok_button = add_group_dialog.FindWindow(id=wx.ID_SAVE)
         assert isinstance(self.ok_button, wx.Button)
         return self
     
diff --git a/src/crystal/util/wx_dialog.py b/src/crystal/util/wx_dialog.py
index 4be14fa5..7756f4b4 100644
--- a/src/crystal/util/wx_dialog.py
+++ b/src/crystal/util/wx_dialog.py
@@ -67,3 +67,24 @@ def set_dialog_or_frame_icon_if_appropriate(tlw: wx.TopLevelWindow) -> None:
     # 2. KDE: Define app icon in the top-left corner and in the dock
     if is_windows() or is_kde_or_non_gnome():
         tlw.SetIcons(wx.IconBundle(resources.open_binary('appicon.ico')))
+
+
+def CreateButtonSizer(
+        parent: wx.Dialog,
+        affirmative_id,
+        cancel_id=wx.ID_CANCEL,
+        ) -> wx.Sizer:
+    """
+    Has a similar effect as wx.Dialog.CreateButtonSizer() but supports any
+    value for the `affirmative_id`.
+    """
+    sizer = wx.StdDialogButtonSizer()
+    
+    affirmative_button = wx.Button(parent, affirmative_id)
+    affirmative_button.SetDefault()
+    sizer.SetAffirmativeButton(affirmative_button)
+    
+    sizer.SetCancelButton(wx.Button(parent, cancel_id))
+    
+    sizer.Realize()
+    return sizer