In Firebug, how to tell what is overriding a style?

Question

I have this css:

fieldset li {  
padding-bottom: 0em;  
}  

However, it wasn\'t behaving properly, and using firebug, I see that style has

Answer 1

If you select the misbehaving item in question, it should give you a list of all the styles applied to it. The bottom should have the most specific styles. If you start at the fieldset li style, you should be able to scroll down until you see one that has overridden it.