Seamless doesn't work, size changes when minimised

[Markjt]

I am running a windows 10 machine 16GB i7 4077 cpu. I just upgraded to VB 5.0.14. In the last version and this one when I am in seamless mode, if I minimise the guest and come back to it later, it looks like it has gone to scaled mode - a white area around a much smaller screen, seamless is then grayed out in the menu and I have to reboot to get seamless back to normal. Any ideas? Also if I start a program that needs administrator permissions the screen goes small with the dialogue box barely visible. It goes back to normal when I OK the dialogue, but it shouldn't do that!