DocumentWindow Resizability when used as a component?

How can I get my documentWindow object, which is being used as a component inside of a mainContentComponent to be resizable?  


It seems that the setResizable(), setResizeLimits() methods only apply if the DocumentWindow object is addedToDesktop=true.

AFAIK it works the same as a child component..? There's a demo of this in the big juce demo, under "MDI"