Sticking Gear Shifter

It is about the gear shifter in my 1998 Saab 900 SE Turbo Convertible that once in a while gets stuck so I cannot move it to other position after starting the engine unless I back the car. When I start backing, the car gets a jolt as if it is overcoming some clamping resistance, and then the gear shifter becomes free.

I've checked if it occurs only in cold climate but detected no pattern as to when it would happen.

Another problem that I should be able to solve before the winter season is that my rear window defroster is not working. The button for the front defroster lights up when I press it on the dashboard but the button for the rear window does not.

Any assistance solving these two issues is heartily welcome.