The fiddles on top of our cabinets were not high enough. I found a bathroom shelf called BAREN which is made of tempered glass and has nicely rounded corners. It is meant to be mounted horizontally, but I mounted it vertically just inside the existing fiddles on top of the lockers. It looks as if it belongs there, and since it is about 40 mm high it can keep quite a lot of “stuff” in place. IKEA no longer sells the BAREN but a newer version called VOXNAN, shown below, is actually sturdier. Click on the picture for details.