Double-click crashes focal

[kstenschke]

Double-clicking on a cell causes focal to crash with a "segmentation fault (core dumped)" error

[ohwgiles]

I think this happens when you have no calendars defined (or shown), and it's due to this code. A quick fix would be to do nothing if there are no items in the wv->calendars list. As part of a more complete solution, the user needs a way to select which calendar the new event will be attached to, but I'd prefer to treat that as a separate enhancement issue.

[kstenschke]

i will have a look at it than and send a PR, thanks for pointing me to the probably related code already.