Cover coming loose between 2 windows

[Carl123]

Hi,
At the front of me house, I got the windows set which is made up of 2 window frames at 45 degrees to each other. There was a cover put between these 2 windows to cover the gap. Now the cover is coming loose.
What can i use to stick it back together? Superglue didn't work.

 

[Selfdoz]

All sorts of adhesives.
Maybe even just a good outdoor weathering caulk?
Suggest to go and ask at the hardware store. Too many products out there.depends on gap and adhesion.
Would stay with a miu product for longetivty and the least movement with temperature changes.
Let us know.