Hi I have a Focus 2008

The rubber on top of the Front windscreen has become loose, I was cleaning the car and wiped over it and it poped out I have tryed to pop it back in but at moterway speed it comes out again, Could someone tell me dose the rubber have to be attatched to the windscreen or is it just ok to stick it down with something ,Im not sure if its just commetic or it should be put back in by ford Im a bit worried as to what to do about it

Thank you x


Thank you very much everyone that put my mind at rest,I will get some Tiger Seal online and use that thank you x