How can a browser's cell determine which matrix it is in?

FROM : Graham
DATE : Sun Jun 04 21:09:58 2006

I have some NSBrowserCell subclasses that I am using in my NSBrowser.
The display data for the cells is loaded asynchronously when the cell 
needs to display (delegate method).
When the data has loaded (in a separate thread) the cell needs to 
draw itself and the only method that seems to work is to drawCellAt 
in the matrix, but this requires me to pass a ref to the matrix to 
the cell which feels wrong.
Is there a way that a cell can find out which matrix it is in? I 
tried walking up the superview chain, but this does not work since 
the cell's NSControl is not in the view hierarchy at the point the 
delegate's willDisplayCell is called.