Mouse button keeps clicking held down.
 

If I bind a keyboard key to a mouse button, and then hold down the mouse button, it will repeat.

So, If I bind keyboard key J, to a mouse button and hold it down, it will go, "JJJJJJJJJ".

Anyone know how I turn that off, and is that illegal on Project 1999?

If it's not allowed, I can try to dig up some of my old mice, to see if they do it to.

That sounds perfectly fine. I use a couple mouse buttons bound to left and right so I can flip through my spell book while moving my cursor in position.

Oh ok. It's not a bad thing that my mouse will repeat the same key?

It's an unwanted side effect.