Graphical glitches when using OpenGL compositor in KDE

[jhdl]

I get similar glitches - artifacts/copies of the mouse pointer.

I'm running Ubuntu Gnome 16.04 (not KDE). And using the Nouveau driver. I have a Dell XPS 15 9550 with nVidia gpu. Dell D3100 dock. Latest (May 16) display link driver.

The artifacts occur when running the mouse past window titles/menu bars, side scroll bars, and other such "boundaries". Some clean up after a few seconds, others clean up if you grab and drag a window.

Here's a picture for an example: https://drive.google.com/open?id=0B7...zlNc0xRWmt5S0k (attached, too)