What's the trick for installing the vinyl trim?

Over the past six years I've had to replace the vinyl trim (3 times) that runs from the front bottom of the trailer, through the push/pull handle, over the top and finally to the rear bottom. The first time I used trim from Amazon and within two years it was cracking. So I got some from a local RV dealer. Last year it came undone while on the road, so I ordered a thicker/heavier version of it from Amazon and installed it on both sides. Last week while on the road, one side came loose from the rail and was flapping in the wind, even though it was still attached by the screws under the front, and back and under the handle.

So how do I install this and prevent a repeat of last week? Glue or silicone sealant on the screw heads?

Thank in advance for any guidance.