Strange scrolling arrows connected to Mouse cursor

Well, I've got an annoyance I'd really like to get rid of in regard to some setting somewhere in Windows 7 (I think). I'm on a web page within Firefox, usually of the type that does not automatically expand to fill the view from edge-to-edge. When I start trying to scroll down the page using my mouse scroll button, the mouse icon turns into this pointer that has indicators for left, right, up, and down. No problem thus far, but when I release the mouse scroll button, the thing stays on the screen and the view of the page often shifts out of sight to the left or right. I have to click again on the page before moving my cursor to disable this pointer. Either I have some setting in my mouse setup wrong, or I'm going to have to disable this scrolling support altogether as it is not working as I think it should be. All I want to occur, when I start using that scroll button, is for the page view to shift downwards. Seems like a simple thing but it tends to drive me nuts in trying to interact with some sites!