I'm having a problem with my rack (a good 50 pounds in an 8-space rack) sliding around on top of my 2X10 cabinet. The rack does have rubber feet, but it doesn't seem to matter when I hit certain notes on the E or B-string (varies per instrument). The other night, the rack slid right off the front. Luckily I was standing in front of it, so there was no damage except to the back of my knee. Are there any products out there, or makeshift remedies?