This will cause it to appear on the task bar but this is a bad idea. When you hide the contents of the floating window the window is set to be hidden but would still appear as an entry on the task bar. So you would have an entry per floating window includes those currently hidden. Plus that does not make it appear in the ALT+TAB list because the floating windows are children of the main window and the ALT+TAB list only shows top level windows.
FYI, Phil, the scenario we are trying to support is something like Google Chrome's functionality: drag a tab out of the tab control and make a new window.
Although it looks like the docking system is almost the same as what you need, in practice I do not think it can do this, even with event handling to tweak actions. The floating windows creates are not top level windows but instead owned by the main form.
I cannot guarantee it will work as expected when you make fundamental changes. You can give it a try and see it is works. But you might find incorrect behaviour that is hard to then fix.