String Furniture desk back bar bracket

When putting a String Furniture desk shelf on the highest layer of your panel, the back bar will not be able to clamp to anything. 

By using this bracket and adding a little bit of felt in between, it will add some friction to keep the bar into place.

I've printed it fully solid to keep the friction, add some extra felt if it is too loose. For me, 2x 0,5mm worked.