Mouse tilt buttons only work when window is not "active"?

For some reason I have a window where when it is active and I am working within it the vertical scroll will work on my mouse but not horizontal. When I click out of the window and mouseover it both scroll functions will work. Im not sure if it is a setting or not but it only does this with Microsoft Excel. Every other application works fine when the window is selected.

Question by NickHallick on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.