Can't get Firebug to work with Sass --debug-info output

[Jeremy Flight]

I have:

• FF v 23.0.1
• FireBug v 1.12.1
• Sass v 3.2.10
  

I create .scss CSS files which Sass compiles into .css files.  I use the --debug-info option to get line numbers included in the .css file that point me to the corresponding line in the .scss source file.  FireSass is installed to make this work.

All of a sudden, FireBug no longer shows line numbers.  Neither does it react correctly if I change a CSS rule in that nothing changes in the browser window and my change is rejected when I press the enter key!

If I compile the .scss file without using the --debug-info, Firebug behaves perfectly normally.

Anyone experienced similar problems or have any ideas what's causing this?