My Mouse Cursor Moves In-Game

[Wyzilla]

So, for the longest time I thought I'd just deal with this bug, but I'm ripping my hair out because of it. I've been experiencing this since I started playing Warframe. When I play the game, my mouse cursor still "exists" and moves as I look around while running and gunning. For example, while I'm running around shooting, the cursor will invisibly drift into my mini-map and I can hear it clicking as it drifts open options. When I open up the chatbox, the cursor as usual reappears, but I see the evidence of it moving. For example-

 

1) At the start of every game (because of this bug), I press T and move the cursor into the upper-right corner to buy myself the most time until I have to readjust.

 

2) After a minute or two, I'll then press T to find the cursor has invisibly drifted into the minimap or the middle left of the screen. This prevents me from turning normally when I try to turn left, and can result in aiming bugging out. Also, sometimes if I click it while it's at the edge of the screen, it'll click me out of the game and onto desktop. I'll then have to select the game on the taskbar to un-minimize it and bring the game back up.

 

Is there any way to fix this? Is this a known bug or a new one? Is it because I'm using Windows 8 instead of Windows 8.1?