virtualbox.org

When running Ubuntu 10.10 x86, (I am going to guess other OSs too), If compiz is enabled and then you proceed to disabled mouse integration with the hotkey or the option on the menu, the mouse becomes invisible. If compiz is turned off, this does not happen.

My host OS is Windows 7 x64.

Known issue. This ticket (http://www.virtualbox.org/ticket/7534) has a similar result for OpenGL applications on a Windows Guest. I haven't found an existing ticket for this as a whole for Linux Guests. Please create one in the Bugtracker (separate account needed). That's the only way it can be fixed.