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Fix COMError crashes and performance in Thunderbird #19

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Fix COMError crashes and performance in Thunderbird #19

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e39b4c6
Fix COMError crashes and performance issues in Thunderbird appModule
Mar 15, 2026
4039db0
Improve startup focus and message reading in Thunderbird
Mar 15, 2026
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264 changes: 185 additions & 79 deletions addon/appModules/thunderbird.py
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,7 @@
from gui import NVDASettingsDialog
from gui.settingsDialogs import SettingsPanel
from tones import beep
from _ctypes import COMError

try:
from NVDAObjects.IAccessible.mozilla import BrokenFocusedState as IAccessible
Expand All @@ -27,6 +28,7 @@
import gui
import scriptHandler
import speech
import textInfos
import treeInterceptorHandler
import ui
import winUser
Expand Down Expand Up @@ -55,107 +57,196 @@ def __init__(self, *args, **kwargs):
self.messageHeadersCache = dict()
self.docCache = None
self.previewPane = None
self._startupFocusDone = False
NVDASettingsDialog.categoryClasses.append(ThunderbirdPanel)

if int(self.productVersion.split(".")[0]) < 115:
self.terminate()
raise RuntimeError(_("The addon Mozilla Apps Enhancements is not compatible with this version of Thunderbird. The application module will be temporarily disabled."))

# Thunderbird starts with a Home tab before the Inbox loads (~3-4s).
# Schedule a delayed focus attempt after the Inbox has had time to load.
wx.CallLater(4000, self._delayedStartupFocus)

def terminate(self):
NVDASettingsDialog.categoryClasses.remove(ThunderbirdPanel)

def chooseNVDAObjectOverlayClasses(self, obj, clsList):
try:
role = obj.role
except COMError:
return
# Overlay list of messages
if obj.role == controlTypes.Role.TREEVIEWITEM or obj.role == controlTypes.Role.TABLEROW:
if role == controlTypes.Role.TREEVIEWITEM or role == controlTypes.Role.TABLEROW:
try:
if obj.parent:
if obj.IA2Attributes["xml-roles"] == "treeitem" or obj.parent.IA2Attributes["xml-roles"].startswith("tree") or obj.parent.IA2Attributes["tree"] == "true":
parent = obj.parent
if parent:
# Check obj attributes first to avoid extra parent COM call
if obj.IA2Attributes.get("xml-roles") == "treeitem":
clsList.insert(0, ThreadTree)
except KeyError:
pass
except AttributeError:
elif hasattr(parent, "IA2Attributes"):
parentAttrs = parent.IA2Attributes
if parentAttrs.get("xml-roles", "").startswith("tree") or parentAttrs.get("tree") == "true":
clsList.insert(0, ThreadTree)
except (KeyError, AttributeError, COMError):
pass
elif obj.role == controlTypes.Role.LISTITEM:
elif role == controlTypes.Role.LISTITEM:
try:
if obj.IA2Attributes["id"].startswith("threadTree-row"):
if obj.IA2Attributes.get("id", "").startswith("threadTree-row"):
clsList.insert(0, ThreadTree)
except (KeyError, AttributeError):
except (KeyError, AttributeError, COMError):
pass
# Tabs
elif obj.role == controlTypes.Role.TAB:
if obj.parent.role == controlTypes.Role.TABCONTROL:
if hasattr(obj.parent, "IA2Attributes") and "id" in obj.parent.IA2Attributes:
if obj.parent.IA2Attributes["id"] in ("tabmail-tabs","event-grid-tabs"):
elif role == controlTypes.Role.TAB:
try:
if obj.parent.role == controlTypes.Role.TABCONTROL:
if hasattr(obj.parent, "IA2Attributes") and obj.parent.IA2Attributes.get("id") in ("tabmail-tabs","event-grid-tabs"):
clsList.insert(0, Tab)
elif obj.role == 8:
if obj.parent and hasattr(obj.parent, "IA2Attributes") and "id" in obj.parent.IA2Attributes and obj.parent.IA2Attributes["id"] == "quickFilterBarContainer":
clsList.insert(0, QuickFilter)
except (AttributeError, COMError):
pass
elif role == 8:
try:
if obj.parent and hasattr(obj.parent, "IA2Attributes") and obj.parent.IA2Attributes.get("id") == "quickFilterBarContainer":
clsList.insert(0, QuickFilter)
except (AttributeError, COMError):
pass

def _get_statusBar(self):
return shared.searchObject((("container-live-role","status"),))

def event_nameChange(self, obj, nextHandler):
if obj.role == controlTypes.Role.DOCUMENT:
self.previewPane = obj
try:
if obj.role == controlTypes.Role.DOCUMENT:
self.previewPane = obj
except COMError:
pass
nextHandler()

def _threadTreeExists(self):
"""Check if the thread tree is present in the accessibility tree."""
try:
return shared.searchObject((
("id", "tabpanelcontainer"),
("id", "mail3PaneTab"),
("id", "mail3PaneTabBrowser"),
("id", "paneLayout"),
("id", "threadPane"),
("id", "threadTree"),
)) is not None
except (COMError, AttributeError):
return False

def _delayedStartupFocus(self):
"""Called ~4s after init, once Thunderbird's Inbox tab has had time to load."""
if self._startupFocusDone:
return
self._startupFocusDone = True
# Don't interrupt if user already navigated to the message list
focus = api.getFocusObject()
try:
if hasattr(focus, "IA2Attributes") and focus.IA2Attributes.get("id", "").startswith("threadTree-row"):
return
except (COMError, AttributeError):
pass
# Only proceed if the inbox is actually loaded
if not self._threadTreeExists():
return
# Use F6 (Thunderbird's pane cycling) to properly engage keyboard focus
self._f6RetryCount = 0
self._cycleToThreadPane()

def _cycleToThreadPane(self):
"""Send F6 and verify focus landed on the thread tree. Retry up to 4 times."""
if self._f6RetryCount >= 4:
return
self._f6RetryCount += 1
KeyboardInputGesture.fromName("F6").send()
wx.CallLater(300, self._checkThreadPaneFocus)

def _checkThreadPaneFocus(self):
"""Check if F6 landed on the message list (not the folder tree). If not, try again."""
focus = api.getFocusObject()
try:
if hasattr(focus, "IA2Attributes") and focus.IA2Attributes.get("id", "").startswith("threadTree-row"):
return
except (COMError, AttributeError):
pass
self._cycleToThreadPane()

def event_gainFocus(self, obj, nextHandler):
if obj.role == controlTypes.Role.BUTTON and obj.parent.role == controlTypes.Role.TABLECOLUMNHEADER:
try:
if "id" in obj.IA2Attributes:
#TRANSLATORS: Indicates the table column in which the focused control is located
obj.description = _("Column {pos}").format(
pos = int(obj.parent.IA2Attributes["table-cell-index"])+1
)
except:
pass
try:
if obj.role == controlTypes.Role.BUTTON and obj.parent.role == controlTypes.Role.TABLECOLUMNHEADER:
if "id" in obj.IA2Attributes:
#TRANSLATORS: Indicates the table column in which the focused control is located
obj.description = _("Column {pos}").format(
pos = int(obj.parent.IA2Attributes["table-cell-index"])+1
)
except (COMError, KeyError, AttributeError):
pass
nextHandler()

def event_focusEntered(self, obj, nextHandler):
if obj.role == controlTypes.Role.TOOLBAR and obj.firstChild.role == controlTypes.Role.TABCONTROL:
obj.isPresentableFocusAncestor = False
# Presentation of the table header where the columns are managed
if obj.role == controlTypes.Role.GROUPING:
obj.isPresentableFocusAncestor = False
if obj.role == controlTypes.Role.TABLE:
if hasattr(obj, "IA2Attributes") and "class" in obj.IA2Attributes and obj.IA2Attributes["class"] == "tree-table some-selected":
obj.isPresentableFocusAncestor = False
if obj.role == controlTypes.Role.TABLECOLUMNHEADER and obj.firstChild.role == controlTypes.Role.BUTTON:
obj.isPresentableFocusAncestor = False
if obj.role == controlTypes.Role.TABLEROW:
focus = api.getFocusObject()
if focus.role == controlTypes.Role.BUTTON and focus.parent.role == controlTypes.Role.TABLECOLUMNHEADER:
obj.role = controlTypes.Role.TABLEHEADER
obj.isPresentableFocusAncestor = True
# End of table header presentation
try:
if set(["containingDocument","containingApplication"]) < set([r.relationType for r in obj._IA2Relations]):
if obj.objectWithFocus().role == controlTypes.Role.DOCUMENT:
speech.cancelSpeech()
except NotImplementedError:
role = obj.role
except COMError:
nextHandler()
return
try:
if role == controlTypes.Role.TOOLBAR:
if obj.firstChild.role == controlTypes.Role.TABCONTROL:
obj.isPresentableFocusAncestor = False
# Presentation of the table header where the columns are managed
elif role == controlTypes.Role.GROUPING:
obj.isPresentableFocusAncestor = False
elif role == controlTypes.Role.TABLE:
if hasattr(obj, "IA2Attributes") and obj.IA2Attributes.get("class") == "tree-table some-selected":
obj.isPresentableFocusAncestor = False
elif role == controlTypes.Role.TABLECOLUMNHEADER:
if obj.firstChild.role == controlTypes.Role.BUTTON:
obj.isPresentableFocusAncestor = False
elif role == controlTypes.Role.TABLEROW:
focus = api.getFocusObject()
if focus.role == controlTypes.Role.BUTTON and focus.parent.role == controlTypes.Role.TABLECOLUMNHEADER:
obj.role = controlTypes.Role.TABLEHEADER
obj.isPresentableFocusAncestor = True
# End of table header presentation
elif role == controlTypes.Role.INTERNALFRAME:
try:
relTypes = {r.relationType for r in obj._IA2Relations}
except (COMError, AttributeError):
relTypes = set()
if {"containingDocument", "containingApplication"} < relTypes:
focusedObj = obj.objectWithFocus()
if focusedObj and focusedObj.role == controlTypes.Role.DOCUMENT:
speech.cancelSpeech()
elif role == controlTypes.Role.SECTION:
if hasattr(obj, "IA2Attributes") and obj.IA2Attributes.get("id") == "quickFilterBarContainer":
obj.role = controlTypes.Role.FORM
obj.isPresentableFocusAncestor = True
elif role == controlTypes.Role.LIST:
if hasattr(obj, "IA2Attributes") and obj.IA2Attributes.get("id") == "unifiedToolbarContent":
obj.isPresentableFocusAncestor = False
except (COMError, NotImplementedError, AttributeError):
pass
if obj.role == controlTypes.Role.SECTION and hasattr(obj, "IA2Attributes") and "id" in obj.IA2Attributes and obj.IA2Attributes["id"] == "quickFilterBarContainer":
obj.role = controlTypes.Role.FORM
obj.isPresentableFocusAncestor = True
if obj.role == controlTypes.Role.LIST and hasattr(obj, "IA2Attributes") and "id" in obj.IA2Attributes and obj.IA2Attributes["id"] == "unifiedToolbarContent":
obj.isPresentableFocusAncestor = False
nextHandler()

def event_documentLoadComplete(self, obj, nextHandler):
focus = api.getFocusObject()
if isinstance(focus, ThreadTree) and controlTypes.State.COLLAPSED not in focus.states and config.conf["thunderbird"]["automaticMessageReading"]:
api.setFocusObject(obj)
treeInterceptor = treeInterceptorHandler.getTreeInterceptor(obj)
api.setFocusObject(focus)
if treeInterceptor:
try:
info = treeInterceptor.makeTextInfo("all")
# Limit the range before extracting text to avoid processing entire large messages
info.collapse()
info.move(textInfos.UNIT_CHARACTER, 4000, endPoint="end")
text = info.text
except:
pass
else:
text = None
if text:
ui.message(
text=info.text,
brailleText="\n".join((api.getFocusObject().name, info.text)))
text=text,
brailleText="\n".join((focus.name, text)))
nextHandler()

def event_alert(self, obj, nextHandler):
Expand Down Expand Up @@ -399,26 +490,36 @@ class ThreadTree(IAccessible):
@property
def document(self):
doc = self.appModule.previewPane
if not doc or not doc.role:
try:
if not doc or not doc.role:
return None
except COMError:
return None
else:
return doc
return doc

def initOverlayClass(self):
if not self.IA2Attributes["id"].startswith("all-"):
self.setConversation()
try:
attrId = self.IA2Attributes.get("id", "")
if not attrId.startswith("all-"):
self.setConversation()
except COMError:
pass

def setConversation(self):
if controlTypes.State.COLLAPSED in self.states:
state = _("Collapsed conversation")
elif controlTypes.State.EXPANDED in self.states:
state = _("Expanded conversation")
else:
state = None
if state:
self.name = "{}, {}".format(
state,
super(ThreadTree, self).name)
try:
states = self.states
if controlTypes.State.COLLAPSED in states:
state = _("Collapsed conversation")
elif controlTypes.State.EXPANDED in states:
state = _("Expanded conversation")
else:
state = None
if state:
self.name = "{}, {}".format(
state,
super(ThreadTree, self).name)
except COMError:
pass

def event_stateChange(self):
self.setConversation()
Expand Down Expand Up @@ -461,14 +562,19 @@ def script_readPreviewPane(self, gesture):
script_readPreviewPane.__doc__ = _("In message list, reads the selected message without leaving the list.")

def readPreviewPane(self, obj):
api.setFocusObject(obj)
api.setFocusObject(self)
treeInterceptor = obj.treeInterceptor or treeInterceptorHandler.getTreeInterceptor(obj)
if not treeInterceptor:
# Tree interceptor may need focus to initialize; swap focus only as a fallback
api.setFocusObject(obj)
api.setFocusObject(self)
treeInterceptor = obj.treeInterceptor
if not treeInterceptor:
return
try:
info= obj.treeInterceptor.makeTextInfo("all")
info = treeInterceptor.makeTextInfo("all")
except:
pass
else:
ui.message("{title}{body}".format(
return
ui.message("{title}{body}".format(
title = obj.name+"\n" if controlTypes.State.COLLAPSED in self.states else "",
body=info.text))

Expand Down