Which is shortcut to exit scale mode in Oracle VirtualBox Windows 7 host

Which is shortcut to exit scale mode in Oracle VirtualBox Windows 7 host

To exit scale mode

Right Ctrl ) + C

It's the ctrl button at your keyboard, not right click + ctrl + c 

If Right Ctrl (Host Key) + C does not work (there have been some issues on Ubuntu), do the following:

1) File > Preferences > Input on the Virtual Machine which is stuck in Scale Mode

2) Change or Reset the Host Key. There's no need to even save after changing the settings

3) Re-open the Virtual Machine and it should be reset!