Tracking DocumentWindow position

I am trying to create a component that slides out of the side of a DocumentWindow onto the desktop, such that it appears as if its attached to my application’s main DocumentWindow (a good example of this is in AU Lab: show plug-in presets).

I add the component to the desktop and call setTopLeftPosition() to reposition it whenever I get a DocumentWindow::moved() callback; however there is a slight delay when drawing the component, and I get a dragging effect as it moves around the screen. I’ve tried resizing the component so that it is wider, playing around with the focus etc. but it still looks quite unnatural.

Anyone know of any alternatives that I could try? Or if indeed this is at all possible?

Thanks in advance!