[Bug 41606] New: Wrong processing of WM_DROPFILES message, received only by the top level windows.

https://bugs.winehq.org/show_bug.cgi?id=41606

Bug ID: 41606
           Summary: Wrong processing of WM_DROPFILES message, received
                    only by the top level windows.
           Product: Wine
           Version: unspecified
          Hardware: x86
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: winex11.drv
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

Created attachment 55950
  --> https://bugs.winehq.org/attachment.cgi?id=55950
One possible fix of the problem.

Because of wrong implementation, only the top level windows receive
WM_DROPFILES.

The children windows even with set WS_EX_ACCEPTFILES, never accept WM_DROPFILES
and are not a drop target at all.

This bug affects only X11 driver. The Mac OS X driver is implemented properly.

The bug is located in the file "dlls/winex11.drv/xdnd.c".

I will attach one possible fix of this bug in the file "xdnd.diff".

It works for me, but need some revision, because my C programming skills and
knowledge about WINE code tree are very low. This way, the suggested fix can be
far from optimal. Especially the function WindowFromPointDnD can duplicate some
functionality implemented elsewhere.