Defsentence

Ive had this bug many times. Ive also gotten around it. Ive always had it work for me, although it could be different for everyone I guess: This bug occurs at random. It does not affect the action buttons: I will press the action button on the fuel tank of any of my ships. Next, edit the fuel quantity or thrust of your engine, launch, full launch sequence, revert back to editing hangar. Once i return im usually able to start editing again. Its not a fix but it sure beats restarting everytime. Good luck kerbals