Replace the little plastic hold downs - they do get fatigued - and you can often get replacements at the big box stores, or any blind store will have them. If the originals are too far apart on the wall, they pop out easily. Take them off the wall, heat them gently and bend them inward. Let them cool down while compressed and they'll stay that way.
Velcro is also our friend, augment the clips with a piece on the wall and another on the rail.
I FINALLY got around to replacing the faucet in my bathroom with a one handled high rise model.... had it sitting in the bath for months. Replaced the drain too since it was included with the faucet set. Found that the lifter on the original set really didn't open that far, the new one opens a lot more.
The original lifter is adjustable, but it was twisted at a funny angle on my trailer. Try playing with the height adjustment on yours. Might be a quick fix.
Today is a gift,
that's why they call it the present.