Web Inspector: [CSS] One rule appears multiple times in sidebar.

[Eugene Klyuchnikov]

Created attachment 195481 [details]
Demo HTML

In some cases one rule appears several times in sidebar.
Moreover it overrides own values.

See demo HTML and screenshot in attachemts.

[Eugene Klyuchnikov]

Created attachment 195482 [details]
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[Eugene Klyuchnikov]

Created attachment 195483 [details]
Demo screenshot

[Alexander Pavlov (apavlov)]

I'm not sure if we want to fix this at all (but this opinion is by no means authoritative), since this is what WebCore reports to us, and this is how exactly it performs rule matching. Since 

.a, .b, .c { X }

is equivalent to

.a { X }
.b { X }
.c { X }

and all three selector groups (".a", ".b", ".c") match the selected element independently (notice that all of them are black, not grayed-out), the rule is reported thrice. Moreover, selector groups might have different specificities, so the same rule may get reported in different positions inside the cascade, and this may turn useful sometimes. I believe we might want to eliminate repetitive consecutive matches for the same rule, though.

[Eugene Klyuchnikov]

(In reply to comment #3)
> I'm not sure if we want to fix this at all (but this opinion is by no means authoritative), since this is what WebCore reports to us, and this is how exactly it performs rule matching.

Oh, I see. Thank you for explanation.