Hi, I just downloaded the mod on my 1.3.1 install.
In the VAB I have a new tab with rovers and several parts (like Nuclear Reactors) are showing up where they should, but to see most of the MKS stuff itself (Duna Series, Tundra Series, Ranger Series, the constructor docking ports...) I have to view in filters like for resources (electrical), which makes it very inconvenient. I downloaded the mod again but the issue remains; I also tried to put the MKS folder unziped directly in my Gamedata folder, then put the gamedata folder in the gamedata folder and then merged it; only the last option showed parts in the filter, the others didn't work at all.
Any suggestions in how to make all the USI parts go where they should be?