VirtualBox-4.1.10: Mouse gets trapped in the FreeBSD-9.0 guest with additions installed

[Yuri]

I had 9.0 amd64 guest installed under the older VirtualBox. Now host was 
upgraded to 4.1.10, but additions in FreeBSD 9.0 guest were still 4.1.2 
and it worked fine.
Once I upgraded additions to 4.1.10, now mouse began getting trapped in 
the guest window, like there were no additions at all. Otherwise, guest 
still works fine, ex. window resize works.

Yuri