Un-dock a movable window by double-clicking the title bar of the window OR click on the title bar and drag it away from the DWR interface (i.e. rip it off).
To re-dock a movable window drag a floating window over the DWR interface and a docking guide (pictured in the middle of the screen shown below) will appear to specify where the window to should be positioned inside the DWR interface. Drag the window onto the desired directional indicator and let go and the window will dock in that location.
The directional indicators help you re-dock floating windows
