Make it possible to drag the size of the 3D view window to be smaller than the whole viewer window, allowing the various floater windows to be placed next to the 3D view without overlapping it. This would, for example, let you maximize the viewer on a large monitor, resize the 3D view, and then drag your floaters outside the main window. See attached image for how it could look.

Implementation: Add a small drag control to the lower right corner of the 3D window allowing that window to be resized to be smaller than the main viewer window frame.