If confirmed that's really painful (I just lost the 10 templates I used to use

May I suggest to change the behaviour so it delete only the template selected (a mean to clean-up the list).
Best if it does it immediately so multiple templates can be deleted if necessary.
I noticed that nothing really happens until I press Ok. But then the window closes and all my templates were gone!
Before pressing Ok the button clears the input field, no more templates are visible but if I press Cancel they are back on the next session.