Sorry for the trouble there.
GoToMeeting can have weird reactions to displays that are zoomed in or have odd or very high DPI. Could you specify the display settings there, with regards to % zoom and DPI ratio?
Another thing to consider is if you have a docking station between the monitor and your laptop.
Can you describe in detail exactly what you seeing? What settings do you have the GoToMeeting window set to before you move it to your other monitor?
I have the same issue. Going Full screen in GTM on a second monitor does not go full screen but is cut off as per original posting.
A partial workaround is to move the main GTM control panel (in desktop version) to the screen that you wish to go full screen on and then launch full screen. This works but you if you minize the control panel to top of screen it goes back to main display. If you then come out of full screen and back in on presentation window it happens again .... so need to be moving the menu window back and forth.
I have the same pb too so : the window won't go further than half height screen when trying to maximize it on the second monitor, its height is locked. If I change zoom : it's just zooming inside the window. But the window itself won't get higher.
Precision : it hasn't always been like that, previously, I was able to go anywhere on the second monitor : at least when resizing the not maximized format
Connexion is through HDMI, second monitor is a TV screen 3840x2160 when my main laptop screen is 1920x1080 (Dell, Intel)
Sorry to hear about that strange behavior!
Since the problem began, have you visited your PC and/or graphics card manufacturer websites for any available driver updates?