I loved having VirtualBox on my Mac with a Windows 7 and Windows 8.1 client, but after the update 4.3.16 it's becoming a pain in the @ss.

Before the update, I usually ran my VM in fullscreen and all I had to do to switch between Mac OS X and Windows, was slide 4 fingers to left and right, to switch between windows. After updating to 4.3.16, when I do that towards the fullscreen windows, it's simply a grey screen as seen here: puu.sh/bBEWS/73b09e91af.png
and it quickly slides back into the Mac OS X by it self. I have to click the icon puu.sh/bBF0G/94641148c0.png to slide over to the Windows.
I'm running Mac OS X version 10.9.4 and VirtualBox Guest Additions have also been updated in the VMs.
Please let me know if you need any other information.
Kind regards,
Thomas