[Bug 4964] New: MDI child not informed of max/minimization

[Wine Bugs]

http://bugs.winehq.org/show_bug.cgi?id=4964

Summary: MDI child not informed of max/minimization
           Product: Wine
           Version: 0.9.10.
          Platform: All
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: wine-x11driver
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]

Wine does not send WM_SIZE message to MDI child if it has been 
maximized/minimized so that its size in pixels remains unchanged.

According to MSDN:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/winui...
, WM_SIZE should be sent also if the window has become max/minimized, regardless
of whether its size in pixels has changed.

In Wine the WM_SIZE message is sent if the flag SWP_NOCLIENTSIZE is not set
(see dll/user/defwnd.c, DEFWND_HandleWindowPosChanged(...) ).

However, this flag is set always (see dll/x11drv/winpos.c, 
SWP_DoWinPosChanging(...) ), unless the window size in pixels has changed
(see dll/x11drv/winpos.c, SWP_DoNCCalcSize(...) ).
Thus, if the size in pixels has not changed, WM_SIZE is not sent at
max/minimization.

A typical situation when this error occurs, is if the application
adjusts the size of MDI child to the size of the frame window,
so that at maximization the actual size in pixels turns out to be the same.

I will attach a testcase and a patch shortly.