Gnome Shell Extension to add Force Quit Button
Adds a force quit button.
Click the toolbar button, then choose the window you want to force quit.
On accidental click, right click anywhere or press Esc to abort the kill.
Install it from the extensions site
Pack using
gnome-extensions pack --podir=po --extra-source=icons --extra-source=convenience.js --extra-source=selection.js --extra-source=utilnotify.js