Flexi storage drawers wont stay closed

[kfillery]

We have a flexistorage unit that we installed a few years ago. It is installed across a wall, with a number of different baskets, frames, hangers and other sections. The baskets all slide out repeatedly by themselves, both empty and when they have things in them. What can we do to stop this from happening? It is really frustrating to have the entire wall of drawers continuously opening.

The wall is straight. 

Short of putting hockey straps around each one, some sort of resistance along the rails or a clip of something at the ends?? All ideas welcome!