id,summary,reporter,owner,description,type,status,component,version,resolution,keywords,cc,guest,host
16370,Main window showing guest freezes after using virtualdesktop on Win7,P-Dog,,"Host: Windows 7, running virtual desktop program Dexpot version 1.6.10, Build 2362. 
Host Video card: NVIDIA GeForce GTX 960
VirtualBox version 5.1.12r112440 (QT5.6.2)

Guest OS: KUbuntu 16.04.1

This behavior started after I just upgraded from VirtualBox version 5.0.?? to version 5.1.12. 

When VB is in fullscreen mode, on the host I switch virtual desktops away from the desktop showing VB guest OS. When I switch back to the host virtual desktop the guest OS screen is frozen. HOWEVER, the VB preview window works. I can see applications switch, and can use a console to tell the machine to reboot. 

The screen does not feeze if the VB guest OS is kept in Windowed mode (not full-screen mode). In fact, switching to windowed mode unfreezes the display. 

The attached log is after the guest screen freezes, then I switch VB to windows mode to unfreeze the display, then switch virtual desktops on the host a couple of times. 
",defect,new,other,VirtualBox 5.1.12,,,,Linux,other