The return value of tkProcessEvent in macosx/tkMacOSXEvent.c is processedEvent, which is either the same as the input argument theEvent, or equal to the return value of tkProcessKeyEvent or tkProcessMouseEvent. As these two functions always return the input argument theEvent, the return value of tkProcessEvent is always the same as the input argument theEvent. Therefore, in tkMacOSXNotify.c we do not need to check for the return value of tkProcessEvent.

The attached patch is relative to the source code after applying this patch: