Unknown timezone popup bug

Whenever I try to modify a calendar event created automatically by a pro planning application in my Gmail calendar, I face the same issue: the timezone isn't recognized by OneCalendar (it displays "unknown" in the timezone field when Google Agenda, for instance, displays "GMT+2").

The bug is that when I try to save my modifications to the calendar entry, I get an "unknown timezone" error popup, and when dismissing the error popup, the event modification screen closes but without saving my modifications. :-(

I think that a better error handling would be to return to the event modification screen after displaying the unknown timezone error popup, allowing the user to update the timezone field and save the event, instead of losing whatever modification was performed.