It depends on what you mean by 1/4

Hello Porsche Family,

Drivers Side Window randomly drops 1/4 in on My 2K Boxster while driving...can tap door or press door panel above inside door latch to correct momentarily until it happens again. Which Micro-switch is the culprit?

If it drops 1/4" then the problem is the microswitch in the door.
If it drops 1/4 of the way down, the problem is one of the two microswitches in the middle of the windshield frame.

The microswitch in the door is located just inside of the outside door handle but you can only access it by removing the door panel trim.
The microswitches in the middle of the windshield frame are directly accessible by unscrewing the shroud near them.