[Bug 54031] New: user32:msg - test_SendMessage_other_thread() broken by WM_WINDOWPOSCHANGING on Windows dual-monitor configs

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=54031

Bug ID: 54031
           Summary: user32:msg - test_SendMessage_other_thread() broken by
                    WM_WINDOWPOSCHANGING on Windows dual-monitor configs
           Product: Wine
           Version: unspecified
          Hardware: x86-64
                OS: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: user32
          Assignee: [e-mail]
          Reporter: [e-mail]

user32:msg - test_SendMessage_other_thread() sometimes gets an unexpected
WM_WINDOWPOSCHANGING message:

msg.c:19053: Test failed: wrong status 00480048
msg.c:19091: Test failed: SendMessage from other thread 5: 0: the msg sequence
is not complete: expected 0000 - actual 0046
msg.c:19091: Failed sequence SendMessage from other thread 5:
msg.c:19091:   0: expected: nothing - actual: MsgCheckProc: 006F025C
WM_WINDOWPOSCHANGING wp 00000000 lp 0022fc40 after 00000000 x 100 y 100 cx 200
cy 200 flags SWP_NOACTIVATE|SWP_NOZORDER (flags 19)
msg.c:19091:   1: expected: nothing - actual: MsgCheckProc: 006F025C 0024 wp
00000000 lp 0022f700 (flags 39)
msg.c:19059: Failed sequence SendMessage from other thread 1:
msg.c:19059:   0: expected: msg 0402 - actual: MsgCheckProc: 007102CA 0402 wp
00000000 lp 00000000 (flags 19)
msg.c:19059:   1: expected: msg 0400 - actual: MsgCheckProc: 007102CA 0400 wp
00000000 lp 00000000 (flags 19)
msg.c:19079: Failed sequence SendMessage from other thread 3:
msg.c:19079:   0: expected: msg 0403 - actual: MsgCheckProc: 007102CA 0403 wp
00000000 lp 00000000 (flags 19)
msg.c:19079:   1: expected: msg 0401 - actual: MsgCheckProc: 007102CA 0401 wp
00000000 lp 00000000 (flags 19)
[53435] msg.c:19087: Test failed: wrong status 00400040
msg.c:19091: Failed sequence SendMessage from other thread 5:
msg.c:18487: Failed sequence SetFocus on a desktop window:
msg.c:18497: Failed sequence SetFocus on another thread window:
msg.c:18517: Failed sequence SetActiveWindow on a desktop window:
msg.c:18527: Failed sequence SetActiveWindow on another thread window:
msg.c:18592: Failed sequence SetFocus on a child window:
msg.c:18592:   0: expected: hook 0009 - actual: CBT: hook 9 (HCBT_SETFOCUS) wp
005e0252 lp 002f0278
msg.c:12896: QS_RAWINPUT not supported on this platform
msg.c:12921: Test failed: wrong qstatus 00000000

See https://test.winehq.org/data/patterns.html#user32:msg

This seems to only happen on dual-monitor configurations, most frequently on
w1064-2qxl but also regularly on w7u-2qxl.