Mouse lag while window compositing is enabled.

Submitted by Chris Jordan

Assigned to Olivier Fourdan @olivier

Description

Enabling window compositing causes laggy mouse movement when compositing is enabled. General desktop use has a slight but bearable lag to mouse movement, however certain applications cause the problem to become a magnitude worse (like moving the mouse through treacle) but only while the mouse is in the windows limits. Once I move my cursor outside the window, it begins to move at its regular speed.

Below are few examples of applications that cause this issue:

Large flash player windows in firefox such as a "popped out" youtube video which has been maximized (note problem only occurs over the embedded flash element, not the entire firefox window)
Maximised VLC windows
Tiles mode dungeon crawl stone soup (crawl-tiles package)
FTL (http://www.ftlgame.com/)

While it's possible that this is a hardware/driver related issue, my PC has quite decent specs. 3.0ghz i7, 12gb ram and amd 5850 gpu.

I will gladly provide further information to help isolate the issue.

Thanks,

Chris Jordan

Version: 4.10.0