[...] It slides quickly until it runs up agains the desk leg then pushes up the side of the desk. I have to reposition this mat several times each day.
Had to return it because the store does not keep it flat but rolls it up and puts tape around it to hold it. The tape leaves a thick glue deposit which is impossible to easily remove. This did not happen in the past when they stored them flat. To add to what I wrote above after several months the plastic breaks down into little very sharp pieces and the mat needs to be replaced.