Recently, the passenger window on my 2006 S40 all of a sudden stopped going down on its own using the "touch and release" feature (where you don't have to hold the button down to raise / lower the window).

I was a bit stressed out since I was sure that this could be an expensive thing to fix...

My old man then tried something - he lowered the window all the way down and kept holding down the button for 5 seconds.
He then raised it all the way back up and again held the button up for 5 seconds.
This apparently resets sensors or something, and would you believe it, it actually worked!!

Very nifty.