wxPython 4/Input gestures dialog: when Cancel button is clicked, make…

… sure to check if the treeview is alive. re nvaccess#7077.

Somehow, when Cancel button is licked, treeview is removed first, yet item selection event is run. Make sure to catch this.

source/gui/settingsDialogs.py

@@ -1977,7 +1977,11 @@ def _formatGesture(self, identifier):
 			return identifier
 
 	def onTreeSelect(self, evt):
-		item = self.tree.Selection
+		# #7077: Check if the treeview is still alive.
+		try:
+			item = self.tree.Selection
+		except RuntimeError:
+			return
 		data = self.tree.GetItemPyData(item)
 		isCommand = isinstance(data, inputCore.AllGesturesScriptInfo)
 		isGesture = isinstance(data, basestring)