I try to debug a javascript function called from Generate Thumbnails plugin in Wordpress. The function uses jquery. So the actual call that I want to debug occurs in jquery.
The problem is that default jquery.js inside Wordpress is minimized and therefore obscure. I changed that file with the uncompressed version of jquery.js file in wp-includes\js\jquery.
But when I debug that function with Firebug's debugger, Firebug still shows me the old, minimized version of jquery:

I copied the location of the script file shown in Firebug and opened it in browser: http://localhost/wordpress/wp-admin/load-scripts.php?c=1&load=jquery,utils,jquery-ui-core,jquery-ui-widget&ver=368b0ffbc13bc55b5ae45ad40a5368d9
This time, the true, uncompressed version of jquery.js was opened.
It seems like Firebug opens the old version of jquery. I restarted the Firefox but it wasn't resolved.
What might be the reason of this problem? Is this Firebug related or Wordpress related?