[WinXP on Mac OS]Mouse/Keyboard input stuck after upgrade

[Yoshi]

My Host is Mac OS X 10.8.3 (Mountain Lion). My VM is Windows XP SP3.
After upgrading VB to the latest 4.2.12-84980, I'm having a critical problem.
When I click the mouse or keyboard in the VM, nothing happens until I click on a host OS application. It seems like the Windows messages are stuck until I switch to the host OS.
I've experienced this behavior in the past after upgrading VB. That time, the problem was resolved after upgrading the guest add-ons. This time, upgrading the guest add-ons (and reboot) did not fix this. Help!

[mpack]

Make sure you aren't grabbing the keyboard off your host in the USB filter settings for the VM.

[Yoshi]

Thanks for reply.
My keyboard and trackpad are bluetooth and the "Bluetooth USB Host Controller" is not set in the USB filters. I tried setting and removing it there but it didn't change things.

[Yoshi]

I've downgraded VBox to 4.2.6. Everything is working fine now. I'm not going to upgrade in the future until I decide to use a newer Windows version.