Debugger not stopping at hard breakpoint in xul javascript.

I'm trying to debug a firefox extension.  I deselected the "Exclude 
Browser Files" from the Debug menu.  Walla, I can now see my extension 
javascript file.

Next, I set a breakpoint where I'd like to stop.  The breakpoint IS 
listed in the breakpoints window and it is a hard breakpoint.

When I execute the code in the extension however, the debugger does not 
stop there.  I've verified that breakpoints DO stop for normal 
javascript/web files.  Is there something  I am missing when debugging 
JS from an extension?  I've tried setting breakpoints at all different 
places in my extension javascript and the effect is always the same. 
The debugger seems to be ignoring them.

I'm using FireFox 2.0.0.3 on Windows.

Thanks
Dennis