Most window motors don't turn off when they run the regulator to the limit. They just keep pushing until you let go of the button, or the internal thermal switch heats up and blocks the flow of current.
In fact, some window motors stop working b/c the thermal switch malfunctions, turning off the motor when it is opening/closing the window normally. I have bought a couple of rebuilt/refurbished motors that "fixed" the problem by disabling the thermal overload switch, but these motors burned up when the control switch got stuck in the on position.