Re: Possible Bug: Mouse drag event records wrong window for release when crossing frames

[martin rudalics <rudalics@gmx.at>]

 > With Emacs 25.2 under MacOS 10.12, I use a mouse key that has bindings on
 > both its depress and release states.  The depress is in a frame with 2
 > windows (one showing *Buffer List* and the other showing hmouse-drv.el).
 > The depress occurs in the *Buffer List* window.
 >
 > The release occurs in another frame and the release window is showing
 > hui-window.el.

Are the frames occupying separate areas on your screen or do they
intersect?

 > Here is the drag event generated.  Element 2 shows the proper depress
 > window but element 3 shows the depress frame rather than the release
 > frame.  And element 3 has a frame rather than a window as its first
 > argument even though the Elisp manual says it should be a window.

IIRC it's a frame when there's no suitable window at the specified
position.  This is largely undocumented and has been sometimes even used
wrongly in the Emacs code base itself.

 > (drag-mouse-2 (#<window 90 on *Buffer List*> 2905 (88 . 467) 4050744642 nil
 > 2905 (12 . 33) nil (4 . 5) (7 . 14)) (#<frame hmouse-drv.el
 > "/Users/bk/Dropbox/emacs/hyperbole/" 0x102f5bde8> nil (-1373 . 463)
 > 4050749802))

The start event seems to look OK.  As for the end event, an X-coordinate
of -1373 does not look reasonable.  Please post results for dragging from
one to another window on the same frame.

Thanks, martin