Here I provide you solution, when unity-tweak-tool keeps your GNOME screen zoom-in and unable to zoom out.
Actually 1 week ago, I install GNOME in my laptop. Then I install unity-tweak-tool magnifier instead of compizconfig magnfier because it was compatiable with gnome. After setting keys for zoom-in /out. When I press zoom-in key, it did not give any respone, so I press it many time. When I restart my laptop, then it makes my desktop screen more zoomed. I press key to zoom-out , But did not worked. And find another methods of zoom- out that did not solve my problem. Such as:
- I uninstall GNOME, then again install it. But did not worked.
- I reset unity-tweak-tool to its default configuration (Disable), But not worked.
- I create new user and login to GNOME. For another user GNOME was working well. But I need to zoom out from my login.
Now I reset GNOME to its default settings using below command. This command worked for me. It zoom out my desktop screen. Now GNOME working well.
$ rm -rf .gnome .gnome2 .gconf .gconfd .metacity .cache .dbus .dmrc .mission-control .thumbnails ~/.config/dconf/user ~.compiz*