[r10317]The schedule edit of convoy in the depot does not regain cursor priority

[RESTRICTED ACCOUNT]

Reproduction Procedure:
1. Edit the convoy schedule in the depot. Leave the dialog and tabs as they are without closing them.
2. Open the schedule tab of another line or convoy.
3. Focus on the schedule editing dialog of convoy, which is in the depot again.
4. Try clicking on the map to add a new schedule.