Balloons can be docked to the border of the 3D viewer.
When dragging the balloon near one of the borders of the 3D viewer, a drop area appears. The width of this drop area is about 60 pixels.

If you drop the balloon in this area, it is snapped to the border of the 3D viewer at the closest location. The line between the balloon and the geometry disappears but the balloon is still bound to the geometry and remains contextual.

When vertical balloons are available, they are not displayed in foreground but are detached from the active command so that the two balloons do not overlap each other.

The size of the icons displayed in the balloon does not change, except when working in a multitouch environment.
To undock the balloon, drag it outside the drop area. The line between the balloon and the geometry is displayed.
Note that when the balloon is dropped onto the left or right border of the 3D viewer...

...it is vertically displayed.
