Cannot edit event when an exchange calendar event is changed to a local calendar event

[xtrailrunner]

Thunderbird version: 52.4.0
OS: Linux Mint: 17.3
Steps to reproduce:

1. Create an all-day event (with no specific time) in the Exchange calendar. It appears in the upper part of the calendar.
2. Open the all-day event and change the calendar type from the Exchange calendar to "Local".
3. Save the modified event. The event appears correctly in the upper part of the calendar.
4. If I try to open the local event I can't.

Thanks
Juergen

[mikini]

Hi, see #610 and report there if the latest v4 beta from the fork doesn't solve the problem.

[xtrailrunner]

I've already installed 4.0.0 Beta4 before I tested.
Thanks Juergen