Fix lag when pressing delete key due to caret timeout change. Incubates

#7201 (issue #6424).

source/editableText.py

@@ -71,17 +71,37 @@ def _hasCaretMoved(self, bookmark, retryInterval=0.01, timeout=None):
 				return (False,None)
 			api.processPendingEvents(processEventQueue=False)
 			if eventHandler.isPendingEvents("gainFocus"):
+				log.debug("Focus event. Elapsed: %d ms" % elapsed)
 				return (True,None)
-			#The caret may stop working as the focus jumps, we want to stay in the while loop though
+			# If the focus changes after this point, fetching the caret may fail,
+			# but we still want to stay in this loop.
 			try:
 				newInfo = self.makeTextInfo(textInfos.POSITION_CARET)
-				newBookmark = newInfo.bookmark
 			except (RuntimeError,NotImplementedError):
-				newInfo=None
-			else:
-				if newBookmark!=bookmark:
-					log.debug("Caret moved. Elapsed: %d ms" % elapsed)
-					return (True,newInfo)
+				newInfo = None
+			if eventHandler.isPendingEvents("caret"):
+				log.debug("caret event. Elapsed: %d ms" % elapsed)
+				return (True, newInfo)
+			if eventHandler.isPendingEvents("valueChange"):
+				# When pressing delete, the caret might not physically move,
+				# so the control might not fire a caret event,
+				# even though the text under the caret changes.
+				# We still want to treat this as a caret move.
+				# Otherwise, the user will have to wait
+				# the full timeout for feedback after pressing delete.
+				log.debug("valueChange event. Elapsed: %d ms" % elapsed)
+				return (True, newInfo)
+			# Some controls don't fire caret events.
+			# Try to detect with bookmarks.
+			newBookmark = None
+			if newInfo:
+				try:
+					newBookmark = newInfo.bookmark
+				except (RuntimeError,NotImplementedError):
+					pass
+			if newBookmark and newBookmark!=bookmark:
+				log.debug("Caret move detected using bookmarks. Elapsed: %d ms" % elapsed)
+				return (True, newInfo)
 			if  elapsed >= timeoutMs:
 				break
 			time.sleep(retryInterval)