I think I'm probably being an idiot, but since a few updates ago I can't seem to use the Mark-level filter. Has anyone else had trouble like this? I took a few weeks off the game, so maybe I'm doing it wrong --- if you want Mark III ships, you hold down III while you click on the icon or draw a selection box, right? If this is a bug, I'm playing a fully-updated version of the game on the Mac, with no expansions.