Comment 1 for bug 723994

Version 2.3.0 fixes a very serious opengl bug

https://bugs.launchpad.net/ubuntu/+source/cairo-dock/+bug/729970

that made video in qt applications turn transparent or disappear entirely, depending on window manager and video backend.

Kdenlive required that cairo-dock use the cairo backend, not the openGL backend, until version2.3.0 came out. Other qt applications involving video reported similar bugs, hope they are also fixed.