Same for me as Krunoslav said. I haven't used the clipper at all lately, but Firefox has been freezing and crashing like crazy lately, and extremely slow. I uninstalled the clipper and it seems to be back to normal. I'm on FF 33.1. I also use 64-bit Firefox Nightly build, which I think is on version 37, and had the same issue - though Nightly has implemented multi-process architecture, so I was getting individual tab crashes right and left instead of the whole browser, which have stopped after uninstalling the clipper.