Any site you use Firebug on will show errors. What you say for the net
panel applies equally to the console and script panels: if you load
page with Firebug off, then open Firebug, you will need to reload to
see the Firebug content for these panels.
In 1.4 the phrase "...panel is enable for a domain..." won't apply.
The panel enablement will be independent of the domain.
But your overall concern, that the error count feature of Firebug will
be largely broken, is quite correct.
However, the feature is already broken because Firefox's support of
error reporting is broken. The page of the errors are not identified
by Firefox (nsIConsoleService), I suppose because it was designed
before tab browsing and AJAX. Firebug tries to work around this
problem by comparing the error URLs to URLS for pages it tracks. But
of course if it is not tracking a page, it has nothing to compare to.
With some extra work we could present the total error counts seen by
Firefox and reset this number every time the Firefox location changes.
For simple cases this will be accurate, but if you have multiple tabs
of AJAX sites open, the numbers will be too high. That leaves us with
unhappy users even if we spend time to implement this function.
Either way we can't win, so I'm inclined to put my work towards
features with more upside.
jjb