f9db65f47f
GTK+ paints some elements like box shadows (which Adwaita likes to (ab)use for borders) outside the rectangle passed to gtk_render_*. This is not an issue if our own invisible frame border is big enough, but in case of non-resizable windows we end up clipping away part of the decoration. Use the newly added gtk_render_background_get_clip() to make sure we always use a mask that is large enough to contain all decorations. https://bugzilla.gnome.org/show_bug.cgi?id=752794