Are there any expected tearing issues with overlapped rendering? I'm seeing tearing when moving another window over a compose desktop window. This is with the OpenGL renderer on Windows.
IRL I'm encountering this with drag and drop -- getting a small flicker sometimes when dragging a file over a window (the window changes its color to indicate that it accepts the drag, but the area where the file is can be 1 frame behind)
Capture attached to show the tearing (warning: strobing)