For as long as I remember my 991's windows have had a strange behavior when you open and close the door.

When the window is completely DOWN with the door closed, if you open the door the window pops UP to have about 1/4" visible out of the door. When you close the door it drops back down again.

It's the exact opposite behavior of the window when it is all the way up, though the reasoning of it happening with the window up is known (strong seal of the window into the seal in the roof).

Does everyone else see this? Any ideas as the the reason for it?

Could it be that with the window up that little bit it is better braced for the shake / impact that's associated with the closing of the door?

I don't see it as anything being wrong with the car, but I am curious as to why it is doing it... there has to be a logical explanation.

 

Perhaps resetting the windows will help. I had a similar problem that was resolved by doing this:

http://www.porscheownersmanuals.com/...-power-windows

Storing end position of the windows after connecting the vehicle battery
The end positions of the windows are lost when the battery is disconnected and reconnected.

One-touch operation of the windows is disabled.

Perform these steps for all windows:

Close window completely once by pulling the switch.
If the window is completely closed, briefly pull the switch again.
Open the window completely once by pressing the switch.

 

I can try reprogramming the window travel (thanks for the procedure!), but I'm not convinced that my car is behaving abnormally.

Your windows stay all the way down where you can't see any glass when the door is open?

 

I believe that's the reason.

 

I've heard others claim it's for anti-rattle reasons previously. Sounds plausible.

 

Yes, when both my driver and passenger door windows are down, they stay all the way down when the doors opened and closed. Even numerous times. What I think is normal behavior is that the come down about half an inch when they are all the way up and you open the door, then close all the way once its closed. I have seen other cars do the same, which I assume allows the doors to close completely more easily.

Give that a reset a try, hopefully that will take care of it.

 

It doesn't need a reset, that's a feature Porsche puts in the cars (raise the window up slightly when the door is opened) to prevent rattle. Its normal.

 

WOW I just noticed as well..... Thanks.

More tricks.