[Bug 53489] New: user32:dde sometimes gets stuck on Windows

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=53489

Bug ID: 53489
           Summary: user32:dde sometimes gets stuck on Windows
           Product: Wine
           Version: unspecified
          Hardware: x86-64
                OS: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: user32
          Assignee: [e-mail]
          Reporter: [e-mail]

user32:dde sometimes gets stuck on Windows:

02fc:dde: 82 tests executed (0 marked as todo, 0 failures), 0 skipped.
user32:dde:0304 done (258) in 120s

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

Based on the available traces, the test always gets stuck somewhere after
test_msg_server() completes (see first child process completion trace), but
before test_ddeml_server() does (missing second child process trace).

This also only happens on Windows 10 but any version thereof (1507 to 21H2).