Comment 1 for bug 1082228

This bug is connected with X11.
Probably this commit fixes the problem:

http://cgit.freedesktop.org/xorg/xserver/commit/?id=3d1051aecbb1955084804133cacd12c7f696833a

There was no release since this commit so the only option is to wait for it.
I assume there is no way that xserver-xorg-core package maintainer (Ubuntu) will apply this patch before the release.

Temporary workaround is to disable VBox mouse integration.