Hello, my black R231 has a black plastic frame around the side windows, i.e. a thicker one at the bottom of the windows and a thinner one at the top around the back. Now I noticed unfortunately, that after the vehicle got wet by rain and then dried again in the sun, are partly discoloured and look “cheeked”. Also a car wash and post-polishing with a microfibre cloth do not provide any remedy. You can only see it in daylight, and it looks superal Is that the same with other R231 drivers, and regardless of that, are these strips always black or in the colour of the car?