Wall Control Shelf Stabilizers

I like the metal shelves that come with wall control kits like this one, because they hold a lot more weight than you'd normally get with other options. However, these shelving units have an annoying design flaw: Unlike most wall control stuff, the shelf itself tends to “jump out” of the vertical support arm tabs holding the shelf in position when there's no weight on them. This means that whenever you clear out a shelf you're risking having the top of the shelf slip out of the arms holding them