I set up Rainlendar first time and added 10 ICS calendars from MT AutoExport directory. On Adding eleven, I dropped down category selection list, then pressed Esc to close it. Instead, all Options window closed, and all calendars added are lost (from settings) and excruciating process of adding calendars one by one in several steps must be repeated.

I've lost much aspiration for assaying Rainlendar. I almost gave up.

Is this expected behavior?

It is expected that Esc key closes a dialog (that's standard Windows behavior) but it shouldn't do that if a combo box is open so that's a bug.

also, standard Windows behavior to close the dialog accepting changes with Enter key, but this happens not when editing calendar settings. So what is the standard for Windows not always the standard for Rainlendar.

How the dialogs work is handled by the framework I'm using and since the same application has to work also on Mac and Linux it is possible that the developers of the framework had to make some compromises. I'll check if it's possible to accept the changes with enter like in normal Windows applications.