I was cleaning the inside of the windscreen not the outside. I’ve used rain dispersant on the external screen with mixed results. The best one I found was Supagard. .Since we had a new windscreen in our car paid for new wipers and rain repel, which is a coating for the windscreen any rain water it seems to run rapidly away .
The problem with some dispersant is the refraction and reflection with low sun. I still fine Fast Glass and Crystal Blue applied and buffed up with kitchen roll,or similar.I was cleaning the inside of the windscreen not the outside. I’ve used rain dispersant on the external screen with mixed results. The best one I found was Supagard. .