Dual Display not working

[nothingbutsound]

Hi all, I have installed virtual box 5.0.20 r106931 on a MacBook Pro (Retina, 15-inch, Mid 2014) running 10.11.4. I have made a windows 10 pro VM, how ever i want to have dual displays. I close the VM down go to settings>display>monitor count change that to 2, save the settings. I then boot up the VM and no monitor appears, so when i click on the monitor button in the VM window i see it says virtual screen 1 and virtual screen 2. virtual screen 1 all options for resize are greyed out, then when i select virtual screen 2 "enable" is also greyed out... am i missing something?
cheers for the help in advance!
Dan

[socratis]

I changed my Win10 VM to have 2 screens, just for a test. When I started the VM, it started with 1 window only. Logged in to Windows and "Enable" was enabled for Virtual Screen 2. Right-click on the Windows desktop, Display settings, there were 2 screens, but you couldn't do too much with screen 2. From the VBox icon, I checked the 2nd screen, and everything became available on the Windows Display settings.

Wait a minute... Have you installed the Guest Additions on your Windows 10 VM? If not, please do. Follow the instructions in the manual.