https://bugs.winehq.org/show_bug.cgi?id=46700
--- Comment #9 from Martin Rosenau mdjrosenau@hotmail.de --- I have been debugging and found out the following:
In the function GetMessageW(), there are function calls to peek_message() and wait_objects(). peek_message() calls wine_server_call().
When peek_message() is called and there is no message available, wine_server_call() will return error code ERROR_NO_MORE_ITEMS in the "reply_header.error" element. Otherwise it will return the message.
When the dialog window that causes the bug is displayed, wine_server_call() only returns WM_TIMER messages.
When I move the mouse pointer inside the notepad++ window, I can see that wine_server_call() is called much more frequently, so wait_objects() seems to detect that there are WM_MOUSEMOVE messages available.
However, wine_server_call() neither returns WM_MOUSEMOVE messages nor any other messages but WM_TIMER. Sometimes even WM_TIMER messages are not returned.