Lupercal

I recently purchased the Theron to replace my worn out old mouse, and for a while it's been passable, not great, but workable; I've generally been okay with it; however, I've started to have this issue wherein a rather obnoxious red arrow appears on my screen whenever I use Mouse 4 or 5. http://i.imgur.com/UjWwCIt.png I've gone through the pathetic array of configuration options available to me, I've tried googling the answer. I don't have a Disable OSD option anywhere and the software updates haven't changed that. How does one go about fixing this? And failing that what's a decent enough mouse to replace this?