I have a 17" Dell Precision, that I have connected to a 22" HP monitor. In normal use, I have presentation mode on so both the laptop screen and the HP monitor are on. (old eyes + lots of work with detailed maps = this solution)
This morning, I start up and everything is a mess. I can use the display settings to see either of the two as my main monitor, but not both like I always have. In the display settings, there’s a box to click to extend my desktop to the external monitor, but all that does is show my desktop picture there, not the active screen.
On this machine, Fn+F8 is the presentation mode switch. I get that to tell me it’s showing both screens, but at the top of the dialogue box it still says presentation mode is off.
Huh?