[Bug 26225] New: An unmanaged window moves wrong way (and disappears) when mouse goes to another X screen

http://bugs.winehq.org/show_bug.cgi?id=26225

Summary: An unmanaged window moves wrong way (and disappears)
                    when mouse goes to another X screen
           Product: Wine
           Version: 1.3.13
          Platform: x86-64
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: minor
          Priority: P2
         Component: winex11.drv
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]

When the window managed by Wine (not by X window manager) is moving with the
mouse and the mouse pointer goes to another screen (for example, at the right
side), the window starts to move down the screen and then dissapears.
It seems it's related to the MotionNotify event handler in
dlls/winex11.drv/mouse.c.
Xlib programming manual describes XMotionEvent as follows:
The same_screen member is set to indicate whether the event window is on the
same screen as the root window and can be either True or False . If True , the
event and root windows are on the same screen. If False , the event and root
windows are not on the same screen. 
…
If the event window is on the same screen as the root window, the x and y
members are set to the coordinates relative to the event window's origin.
Otherwise, these members are set to zero.

But the MotionNotify event doesn't check the same_screen member and passes null
coordinates to the update_mouse_state function and it causes wrong window
positioning.