oinkmaster

Hello all, The following behavior really kills the fun in this game for me: When I build a rocket I change a small part, like a decoupler in the middle of the rocket, the stage configuration of one half of the rocket gets reset to some default. So I have to reconfigure everything for 30 min again etc. How can I prevent this behaviour? Also are there root part changers and subassembly loaders that don't mess up fuel lines and struts? Thank you!