Ubuntu – Nautilus losing theme

I copied a the theme from /usr/share/themes that is close to fit my needs to /home/user/.themes. After copying the folder I removed the settings for the window-managers that I don't use. Now I used that copy to edit the appearance of the theme.

I changed the gnome-shell.css file in the folder of the specific window-manager. (here gnome-shell folder of course) So far I played around with the size of the icons and their spacing in the application overview. The file itself has a few comments which hint to functionality and to the purpose of the parameters. Just look there and play around... if you mess it up just replace it by the original theme. Hope that at least leads into the right direction.

Your Prt Sc key (or whatever it is labelled on your keyboard) is most likely faulty. When gnome-screenshot is installed, that key initiates a screenshot and is not propagated to applications. When it is uninstalled, the key press is ultimately propagated to Google Sheets which results in clearing and editing the selected cell. When pressed continously, it will also prevent you from navigating in nautilus' location bar and immediately close taskbar menus.

To confirm this, install evtest, run sudo evtest in a terminal and select your keyboard. Leave it running. As soon as the problem occurs, don't press any key and switch to the terminal. There will be lines containing KEY_SYSRQ.

The obvious solution is of course replacing the keyboard. However, if it is a builtin laptop keyboard, that may not be an option.

As a workaround, you can remap the key's scancode to a key that usually has no effect, like unknown. I have written instructions for this here. Keep in mind, though, that you won't have a SysRq key then, unless you remap another key (maybe one you never use) to SysRq. This won't prevent the faulty key from sending X key events and it will still interfere with nautilus (but not the taskbar).

Another workaround would be disabling the whole keyboard using xinput --disable [id] where [id] is the device's id you can obtain with xinput list. You'll then have to use an external keyboard, but the faulty key's events are not propagated beyond the X server and won't interfere with applications.