Replying to DonGateley:
Still true on 4.2.6 so I guess there is no interest among the developers to fix this. Heavy sigh.
Your guess is plain wrong. Please bear in mind that you're not the only person using VirtualBox (many million users, and quite some other bug reports), and this implies that the developers have to prioritize issues.
Disabling mouse integration is a VERY unusual setup, only a tiny fraction of the user base even knows that this is an option.
