Hi, I'm mounting windows and canopy on a 1.5 OTS series. But I have some problems with the distance to the window in the corner between the top of the window and the rear of the window on both sides. In the corner the window will not reach/touch the rubber. It seems like the diameter of the edge is smaller than the diameter of the canopy frame/rail. Everything has been dismantled and the windows are new. Are there several types of windows so I may have got the wrong type? Or have I mounted something wrong?