I have been trying to find something like this for a while now. The way I sit, my fingers often trigger the zoom function as I scroll with two fingers. It has been a problem on every browser I have used. This one is the first to actually have something that does this. It seems like a simple plugin, I have no idea. It's great and my wife loves it too since I don't have to beat her after getting mad a breaking the computer....kidding... I would never break my computer.

simple and effective

My otherwise great mouse has a super sensitive scroll wheel and I often zoom in on a page by misstake whenever using a keyboard shortcuts (ie. holding ctrl). Which is super annoying...
This addon is the only way I have found of locking Firefox zoom level. So far it does exactly what i need it to do. Thanx!