Hi,Do you see that black shadow with or without applied patch _GTK_FRAME_EXTENTS patch?
No. It will not be merged if compiz does not get _GTK_FRAME_EXTENTS support so I dont see any reason to spend time on it.
The only problem remains is the black-corner which could probably arises from GTK_FRAME_EXTENT or from the fix of this: https://bugs.launchpad.net/ubuntu/+source/gtk+3.0/+bug/1515561.Might be problem with theme and/or problem with ubuntu patched GTK+ version. Black corners are on csd windows or ssd windows? or both?
Yes and no. Without this patch csd windows looks like they are running without compositor, but with patch shadow area is treated as part of window. Problem is that compiz does not support _GTK_FRAME_EXTENTS so this patch will not be merged.
This is not related to GNOME Flashback. Looks like problem with compiz and/or gnome-terminal.