Cannot edit past event if project code was expired meanwhile

[frankosterfeld]

Scenario:

I've got an event e on February 1st On February 2nd, I want to change the project code for e to a code that is valid on Feb 1st, but expired on Feb 2nd. The task selector doesn't let me select the expired project code, although it is a valid choice for e.

The task selector should not use "now" but the event's end date for the expiry comparison.