Entity Tree: Select first entity initially, if available

src/crystal/browser/__init__.py

@@ -387,6 +387,7 @@ def _create_entity_tree(self, parent: wx.Window, progress_listener: OpenProjectP
         """
         self.entity_tree = EntityTree(parent, self.project, progress_listener)
         bind(self.entity_tree.peer, wx.EVT_TREE_SEL_CHANGED, self._on_selected_entity_changed)
+        self._on_selected_entity_changed()
 
         return self.entity_tree.peer
 
@@ -829,7 +830,7 @@ def start_server(self) -> 'ProjectServer':
 
     # === Entity Pane: Events ===
 
-    def _on_selected_entity_changed(self, event: wx.TreeEvent) -> None:
+    def _on_selected_entity_changed(self, event: Optional[wx.TreeEvent]=None) -> None:
         selected_entity = self.entity_tree.selected_entity  # cache
 
         readonly = self._readonly  # cache

src/crystal/browser/entitytree.py

@@ -86,6 +86,11 @@ def __init__(self,
         bind(self.peer, wx.EVT_MOTION, self._on_mouse_motion)
         # For tests only
         bind(self.peer, EVT_TREE_ITEM_GETTOOLTIP, self._on_get_tooltip_event)
+
+        # Select first top-level entity initially, if available
+        root_children = self.root.children
+        if len(root_children) >= 1:
+            root_children[0].view.peer.SelectItem()
 
     # === Bulkhead ===
 

src/crystal/tests/test_workflows.py

@@ -323,11 +323,7 @@ async def test_can_download_and_serve_a_static_site() -> None:
                 # 1. Test cannot add new root resource in read-only project
                 # 2. Test cannot add new resource group in read-only project
                 selected_ti = TreeItem.GetSelection(mw.entity_tree.window)
-                if is_windows():
-                    # Windows will initialize the selection to the first child of the root
-                    assert selected_ti == feed_group_ti
-                else:
-                    assert (selected_ti is None) or (selected_ti == root_ti)
+                assert selected_ti == feed_group_ti
                 assert False == mw.new_root_url_button.IsEnabled()
                 assert False == mw.new_group_button.IsEnabled()