The plastic "fit in hole" shelf-supports come out too easily, with the result that if someone bumps it,the shelf falls out, along with everything on it.
Each support works by pushing (inserting) its 1/3-inch-long cylinder part into the predrilled hole; four such holes, each with one of these plastic inserts, support the four corners of a shelf.
One way to keep a support from slipping out of its hole would be to glue the cylinder part into the hole.
Disadvantage: you can never get it out again, should you want to change the spacing between the shelves.
Question: is there some kind of a WEAK glue that will hold up to a point, but then will break its bond, allowing you to remove the plastic support?
Thanks!
David