GRA Retrofit: Troubleshooting Wiper Cover Issues

Help!
Today I started installing the GRA (rain sensor) in my Golf IV. The work inside the car wasn't a problem. Then, I removed the windshield wiper arms as instructed to remove the wiper cover. However, the cover is 'stuck on really tight'; the adhesive between the cover and the windshield is very strong. I pulled, wiggled, and sprayed, but nothing worked.
Finally, I've given up for today (it's already dark) and I've noticed that there are two large cracks in the glass in the lowest section.
How do I get this damn cover off? Should I use a hairdryer to warm it up?
Thank you for any advice, and Merry Christmas in advance.
Martin.

Määtes wrote:

How do I get this damn cover off??? Should I use a hairdryer to warm it up?

Simply lift it upwards in a large, even motion. Prying against the disc is dangerous and will inevitably lead to the destruction of the disc (without additional safety measures). The cover is only snapped in, it is not glued!!!

I have already pulled evenly and quite strongly in all directions, including upwards .
I have the impression that the seal around the windshield is stuck to it due to heat, as they are definitely fitting together very tightly. It shouldn't normally be a problem, and the repair manual for the Golf IV doesn't mention anything special about it either.
I'm going to try warming it up with a hairdryer tomorrow; that way, the plastic won't be so brittle.

Happy holidays to everyone,
Martin.

Määtes wrote:

I already pulled evenly and quite strongly in all directions, including upwards . I have the impression that the seal around the windshield is stuck to it due to heat, as they are definitely fitting together very tightly. It shouldn't normally be a problem, and the repair manual for the Golf IV doesn't mention anything special about it either. I'm going to try warming it up with a hairdryer tomorrow; that way, the plastic won't be so brittle.

The cover is neither glued nor does it have any sealant or gasket (at least originally). It simply consists of metal clips that snap into a rail underneath the glass.