Pretty much as the title says. I was in the middle of a launch, altitude around 23000m, when a friend came by for a visit - so I pressed Esc/Pause. I returned all of 10 minutes later to finish up putting the ship into orbit, so I could go entertain, but when I pressed Esc/Resume I got some serious lag. Not only was the ship lagging (fps), but clicking on navigation controls etc also suffered an aching delay. I ended up reverting back to the VAB... still lagging... then just exited the game. Now back in game, things are fine. This is not the first time this has happened however (from Pausing). Any ideas on what's up with this?