If you are in the mechlab, and have the 'Modules' tab open, then select a new mech, you will still show as being in the modules tab, but you'll be looking at the mech build. So you have to click to another tab, then back to modules. This has a 100% occurrence.
It's not an end of the world glitch, but it is annoying when I'm trying to move my modules around. If the new mech would pop up on the modules screen, it would be a fairly quick system, especially compared to systems of yore.

Also, to add to this... Having the 'Mounted weapons' box checked when you change mechs doesn't work, you have to uncheck it, then check it again to make it show only mounted weapons modules.
Edited by Twilight Fenrir, 17 June 2015 - 06:56 AM.
















