Mission Editor Loads S1944

So, I opened up the Mission Editor this morning, and it updated to the latest version. Now when I try to test the mission I'm making (from the ME menu), it... loads Spring 1944 instead of Zero-K. It's the same map and same player names and teamcolours, but I end up with a few British AFVs, a sniper and a Spitfire (not in the same places I put Zero-K units). I have no idea what's going on. If it helps, S1944 was the last mod I downloaded.

I'm not trying to load S44, though, I'm trying to test a mission that uses the latest Zero-K release. Actually, it seems to do this regardless of the Zero-K version I try to use.