I need to prevent the spacebar from scrolling while I am in Firefox. It drives me demented! Every time I lean forward to concentrate, my clothes accidentally brush the spacebar and it sets off a superfast scroll, which gives me a severe shock and loses my place. Help me deactivate that function please. Surely, it must be optional?

In case you're wondering, yes, I do push the keyboard away when I read, but then I bring it forward to take a note in a Word document, and by that time I am so absorbed I don't notice whether or not I've pushed it away again. I have tried to create the habit but can only do it when I start to read, and never when I return to read. The shock and discombolulation physically hurts. Help, please!