What is this for on my Disco??

Been wondering this for a few months now, and I can't see the point of it.

As you can see it is a little plastic thing on the drive and passenger window frame.

Anyone got an idea what it is for???

It's to keep the glass in the channel in the event a child or idiot leans on the glass while it is been wound up.

Or in hot weather when travelling at high speed with windows down they can sometimes not locate properly when winding up. Used to happen all the time in my Vectra, press the up button gets nearly to the top, hits door fram and automatically goes down again due to the anti-trap safety feature.