[Bug 21600] MSGBOX_DlgProc Help button not supported

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=21600

--- Comment #9 from Ken Sharp  ---
I don't have a copy of the original version, and the new version doesn't seem
to touch MSGBOX_DlgProc.

Confusingly it seems as though a Help button is requested but not drawn (File
--> Backup, for example):

002c:trace:dialog:DIALOG_GetControl32     L"Button" L"&Help" 1038, 350, 272,
40, 14, 54010000, 00000000, 00000000

..which may explain why I cannot trigger MSGBOX_DlgProc.

I'll have to come back to this one.