Comment 4 for bug 1407880

WORKAROUND: This shadow turned out to be caused by the GTK3 theme.

Any GTK3 theme setting a shadow for

.window-frame

will cause whatever shadow the theme specifies to appear on most cairo-dock dialog box bubbles and on the application-menu bubble. For some reason it was possible when starting under metacity with -W to remove support for this shadow, even though the GTK theme was the cause of the problem.

The theme css files can be edited to remove all references to a shadow affecting .window-frame, and the border between the now transparent window and the desktop becomes invisible. Since I use a custom GTK3 theme I just needed to find this and modify it.

If any other GTK3 theme generates this shadow, either change themes or modify it as a workaround. I do not know if it is possible to fix this in cairo-dock itself so no GTK theme can make the invisible window boundary around a bubble show a shadow. The code I used bringing in this buq came from the "E17" GTK3 theme, which was the base from which I built my refactored "UbuntuStudio_Legacy" GTK3 theme.

E17 is at

 http://gnome-look.org/content/show.php/?content=163472

I suspect this is not the only theme setting a window shadow