What is causing my mouse speed to max out whenever I click on a window?

What is causing my mouse speed to max out whenever I click on a window?

If this question is too localized or rare, I will gladly delete it.
However, I am hoping that someone can help me out with this.
I am using Windows 7 and I just installed Planetside 2. After I quit the
game for the first time, I noticed an odd behavior that causes my mouse
pointer speed to max out whenever I open a window like IE or switch to
another window that's already open. I bring the speed back down, but it
spikes right back to the top again as soon as I click on another window.
Does anyone know what could possibly be causing this? I am using Logitech
G500. I have never experienced this before until installing Planetside 2.
I uninstalled the game, but I am still experiencing this unwanted
behavior.
Update: I opened my Logitech Gaming Software control panel where I can see
all five of the DPI settings I have available (200, 1200, 2250, 3550, and
5700). When I open it, sure enough, it's set to 5700. I set it to 200,
click an IE window, and go back to the control panel to see that it's set
at 5700 again. This is madness.