Can't Open TFT Editor

[Melth]

So suddenly the world editor opens the Reign of Chaos version and not frozen throne. I have no idea why that is. One moment it was working, then I closed out and opened it back up again and it did the Reign of Chaos editor instead. As if that wasn't bad enough, now The Frozen Throne actually opens Reign of Chaos instead too!

I've been looking around but so far I haven't found a solution for this weird problem. Does anyone know what could cause this?

Edit: Ah ha! The problem was resolved when I closed the MPQ editor. Now both world editor and TFT open normally.