problem with automatic display detection

I have a 2011 13/256 air and every time I disconnect the rgb:mini display adapter after giving a presentation in powerpoint the resolution does not revert back to the native setting. Tonight I tried to plug the adapter back in to see if it would reset the resolution, but the mac display went blue and I had to force restart. The display adapter is not aftermarket, but it works perfectly in every other respect. So I have a few questions

1) Is it normal to have to manually change the resolution back after disconnecting a display?

2) Is there a toggle on the mac to go back and forth between displays (like the function key plus one of the F keys on a PC)?

3) Could this be a problem with the adapter?

 

Thanks for the reply.