[Bug 48820] New: user32:win "unexpected 0x7fff message" Japanese Windows 10 failures

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=48820

Bug ID: 48820
           Summary: user32:win "unexpected 0x7fff message" Japanese
                    Windows 10 failures
           Product: Wine
           Version: unspecified
          Hardware: x86
                OS: Windows
            Status: NEW
          Severity: major
          Priority: P2
         Component: user32
          Assignee: [e-mail]
          Reporter: [e-mail]

The TestBot's w1064v1809-zh_CN configuration runs the tests on Windows 10 1809
in a Chinese locale. This test configuration gets unique failures in
user32:win:

win.c:3852: Test failed: hwnd 007404D2 message 7fff
win.c:3858: Test failed: message 7fff available
win.c:3931: Test failed: hwnd 007404D2/0054050A message 7fff
win.c:3934: Test failed: hwnd 007404D2/0054050A message 7fff

Note how these messages are very similar to the IME messages in bug 48819.
However 0x7fff is a totally unknown message: all I can say about it is that
it's WM_APP-1. So maybe it's another IME system. Maybe not?

See: https://test.winehq.org/data/tests/user32:win.html

However note that quite often WineTest fails to submit its results to
test.winehq.org, typically because it times out. So you can more easily find
the latest failure by looking for the "32 bit WineTest: base VMs" jobs on the
TestBot.

Finally, three of these messages include the window handles which means they
are "always new". Because of this the TestBot will mistakenly attribute the
failure to any user32 patch submitted to wine-devel, which should cause them to
be rejected. So I bumped the priority on this bug.