Problems with WM_DROPFILES

[John Found]

I just realized, that in WINE, my windows receive WM_DROPFILES only if they are
top level windows. All children windows never accept WM_DROPFILES, regardless of
the presence of WS_EX_ACCEPTFILES or calling DragAcceptFiles() for this child window.

In Windows everything works OK and the children correctly receive WM_DROPFILES message.

Is it a bug in WINE, or something OS/WM dependent?

How to fix it? Is it a good idea, for example, to accept the message in the main window and dispatch it to the respective children windows (by using DragQueryPoint) - this approach should work both in WINE and Windows.

WINE v1.9.19 
XFCE4 window manager.