i know what youre talking about. it should be a U clip that holds the crank in place. use a flat tip screwdriver to push one side back, it should pop off. careful, they can go flying into the sunset never to be seen again. i dont know how contour ones go, but ive had this happen a few times.

if its really stubborn, use a second flat tip on the other side, thereby pushing both sides at the same time. careful not to accidentally slip and scratch your door panel.