[jQuery] adding filters in the middle of a selector brings Firebugs warning

[jQuery] adding filters in the middle of a selector brings Firebugs warning


Hi,
If I am doing this:
alert($(".ivts_thead").find("tr:first").find("td").length);
alert($(".ivts_thead tr:first td").length);
I get in both cases the same result, the expected elements are in my
object, but in the second case, I get a Firebug warning saying
"Unknown pseudo-calls or pseudo-element 'first'".
This happens each time I am adding any :filter to any selector which
uses more than one single expression.
Does that mean that I should create my selectors as I did in the first
case? That wouldn't be very handy...
Thanks!
Thomas