voltage dip with pwr windows

Ok, this may be a dumb question, but I gotta ask..

Just noticed this morning...sitting with the Blazer in park, engine idling. I pushed the button to make sure my window was all the way down and noticed the needle dip slightly on the batt/alt gauge, heard the engine sound change at the same time, like it was working just a bit harder.
It's a 1997 Blazer...last alternator was in 2003, got a new battery in December 2009. Surely a single pwer window button wouldn't pull enough to make a noticible power draw would it? Or am I just paranoid?
-Mike

It's normal. Stall condition of motor pulls voltage down and subsequently increases load on the alternator to make up for it.