It’s impossible, for me, to edit the calendars:
What this video i done for you:
https://www.mediafire.com/file/97dc666zbkgmhdt/capture-1.avi/file
I can click “OK” thousands of times, it hasn’t no effect. I tried 3 different browser, i’ve cleaned the cache, tried with ipconfig/ flushdns.
Nothing to do.
P.S. Sorry but the cursor is not visible.