How to get quick succession mouseDown events

FROM : carbonat
DATE : Thu Apr 24 14:22:15 2008

I have implemented a NSButtonCell subclass in the usual way to catch 
mouse tracking. I get the startTrackingAt and stopTracking messages 
called correctly on the click of the mouse. However the 
startTrackingAt  is not quickly called again if I quickly click again 
the mouse, such as if I did a double click. So, what is the way to 
catch *all* the mouse clicks to a NSButtonCell (up and down) even if 
they are performed at a rather quick pace?

Thanks in advance.

Joan