desktop zooms out and 'floats'

[xadder]

I am using Xubuntu 17.04 on a HP Spectre, HiDPI. Normal usage is fine, but occasionally hitting the wrong combination of keys (I think alt+click on touchpad) while trying to change the size of terminal results in the whole desktop becoming too large for the screen. Then, as I move the mouse, all the windows move around. I can reach all parts of the screen with the mouse, but it is very disturbing to have all windows floating around.

The only solution I have now is to reboot, but there must be a better way.
Anything I can do to get back to normal? Thanks!

[Dennis N]

You have probably encountered Xubuntu's screen zoom feature, which can be activated and controlled by holding Alt key down while turning MouseWheel. Turn wheel forward to zoom in, and back to return to normal.

[xadder]

Ah, that did it, thanks! Actually, I'm not using a mouse, just a touchpad, but holding alt and moving on the right edge did the trick