Nice to hear this will be added to the next release. I can image a floatable LayoutPanel boolean field or some such to enable this capability. Using the stateChange event is not really an answer due to the limited information provided in that event, and it would be very awkward anyway for an end user to float a LayoutPanel then have it ‘magically’ redock somewhere outside of their control/input.
You have a great element here in the Docking Layout, but it appears to still need a significant amount of work to get it ready for custom Production environments. Please keep up the good work and continue to improve this element.