So since 1.10 rolled arround I've been experiencing this issue that the "connect" button in the VAB load dialogue doesn't work, I've previously tried it without any mods but the issue persits.
Steps to recreate: Load or build craft 1; open the load menu and click connect
Versions: KSP 1.10.0.2917 64 bit
Mods:
MechJeb 2 (V.2.10.0.0)
Module Manager (V 4.1.3)
Logs (I doubt they help but I can still give it a shot)
https://www.dropbox.com/s/t5k8n2xlts6kvvr/Player.log?dl=0
I've also seen a lot of People complaining on Reddit and Twitter so I doubt I'm the only one, maybe there is a common solution?