GitLab

Merges remote-tracking branch 'berghofer/master'

Otherwise tabs would be using the previous source file.

For example, "<Ctrl>k" is now a suitable shortcut. Moreover, this fixes
default shortcuts for automated strategies being rejected.

Otherwise the default prover might be incorrectly shown to the user. For
example, if the user never set a default prover, the interface shows that
Alt-Ergo (or whatever comes first) is the default prover, while nothing
happens when pressing 'p'.

This makes buttons behave like in most graphical applications, that is,
releasing the pressure outside the button cancels the action.