Just to be clear - I'm not talking about a property being 'greyed out' or struck through; This is a whole CSS rule displayed normally, but on a grey background. Other applied rules display normally, without a grey background. Does anyone know what a grey background means?
The reason I'm asking is, despite the properties not being greyed out or struck through, the rule does not appear to get applied. I'm hoping the grey background is significant and that significance might explain why the rule is not being applied.
Edit
I've been told I should edit the question to make it clear why it's not a duplicate of the question above. I can only repeat that I'm not asking about greyed-out properties; I'm asking about a CSS rule displayed on a grey background. That was what I specified in the original question, above. If you look at the accepted answer to that question you'll see the user was asking about greyed-out CSS properties (why would he accept that answer otherwise?)
Any chance someone could remove the 'duplicate' reference?