Better UI layout for adding objects

When nothing is selected, the transform tools change to addable objects. The reason being that those tools can't be used when nothing is selected so it is better to put in there place an option to add something those tools can work on. This also gives a chance for better organization, the little down arrows would allow the cube to drop down into a flat plane, sphere to circle, you get the picture. I thought it would be a pretty slick design, let me know what you think.