I have had a couple of them apart for various reasons. They are a very simple design, and I appreciate that.
If you tighten the string, the action is stiffer. I imagine this is what you need to do to help them stay up, but that was never the issue with mine.
2017 Escape 5.0 TA (someday soon, I hope
2015 Ford F150 Lariat 3.5L EcoBoost
2009 Escape 19 (previous)
“Most folks are about as happy as they make up their minds to be.” — Abraham Lincoln