https://bugs.winehq.org/show_bug.cgi?id=43728
--- Comment #10 from Panard panard@inzenet.org --- After a bit more source code reading, MsgWaitForMultipleObjectsEx calls are due to dlls/user32/message.c/check_for_driver_events, which are due to PeekMessageW calls (it calls it twice, which is coherent with the counts from the log file).
Maybe there is something around the count_message which is never reset, and hence calls MsgWaitForMultipleObjectsEx each time check_for_driver_evens is called, but it is quite likely to be a symptom and not the cause of the PeekMessageW calls.
But I have a hard time to find what causes these PeekMessageW calls.. probably need to learn how to use winedbg..