Deleting one duplicate of a station in a stop group makes the stop invalid

Issue description

When editing a train line, it is possible to add the same station to a group multiple times. If the station group consists only of multiple copies of the same station, and you delete one of them, the whole stop becomes invalid.

Reproduction steps

1. Load attached save
2. Select the Wood train line
3. Add a station to the group New Field East
4. Select New Field East
5. Delete one of the New Field Easts
   The stop will now consist of no stations and be invalid.

Game version and build number

v0.7.8 (b481)

Operating system

Windows

Attachments

Dupe Example.save

Files not imported: Dupe Example.save

I'm not sure I follow. I'm unable to add one station to the same group multiple times.

I can't recreate it now, either. I'll try some things but there must be some other condition I didn't realize.

No worries, maybe we fixed it in recent updates. If it happens again, please file a new issue with specific steps. Thank you!