I put some of that rubbery stuff that R.V.ers use in the cupboards-cut it to size & glued it to the bottom of my rulers. Than I couldn't see some of the lines. Sooooooooooo I bought some rubber cement. Peeled-clawed-dug what it took to get the rubbery stuff off the back.
Spread the rubber cement on the back of the rulers-let it set overnight & viola-my rulers don't slip. If you find that things are slipping around again- just re apply the cement.
Works for me
I also got one of those lippy rulers today @ Hancocks 50% off.
Gotta cover all the bases. LOL