About dual display in Windows 10, here's a practical tip for those who like me have a laptop display with smaller resolution and then external display with bigger resolution.
As you know, if you set your external display as your primary display in order to be able to watch for instance videos full screen with better resolution or play your games full screen (surprisingly many games only allow full screen on primary display), the Taskbar can be a pain in the you know where. To start with the main Taskbar with notification area disappears under a full screen program:
Screenshot shows Kodi full screen on my primary display (external monitor on the right), Taskbar disturbingly blocking parts of the bottom as soon as I do something on secondary display (laptop's display):
This looks even worse if you use a vertical Taskbar as I do:
Luckily I can simply unlock the Taskbar on primary display (external monitor), drag it to the secondary display (laptop) and place it there where I want to, and finally lock it again. Now I can watch my videos or play a game full screen on the external display which is set as the primary display, while the Taskbar is only shown on the secondary display:
I used Kodi as an example in above screenshots which is not the best example as it can be set to use full screen on secondary display, but especially many games do not have that option available.