I need some help guys, For some reason When I hit the d key in my editor it maximizes the Visual Studio Window.

I've never had this happen before, has anyone else experienced behavior like this? I multitask and have a 49 inch LG monitor. I split the screen using the right side for Visual Studios editor, the left for web browser. Whenever I start typing code and I hit the d key Visual Studio maximizes and fills my screen.

It's real annoying.