I want to style the text for "not opened" tabs via userChrome.css.
I've read somewhere on the Mozilla Wiki that it should be possible using
#content tab:not([selected])
since it was supposed to be "true" for the selected, "false" for unselected and unset for any tabs not accessed yet.
However, this does not seem to apply anymore to Firefox 3.6 (and my set of extensions).
I've seen an attribute "ontap" (which may come from the BarTab extension), which is set (and "true") for any not loaded tabs (BarTab causes tabs on browser startup to not load (fully); they get loaded when being selected the first time).
So, while
#content tab[ontap=true]
may work for tabs that have not been loaded at all, it won't work for tabs opened in the background (i.e. when I open tabs from the current tab in a background tab).
If I remember correctly, "Tab Mix Plus" would add this functionality (and in fact I might be used to it from Tab Mix Plus), but given my current setup of extensions, I want to avoid enabling the whole of Tab Mix Plus for only such a simple feature.
The most relevant installed extensions in this context appear to be: BarTab, Tree Style Tab, ColorfulTabs and Aging Tabs.
Ok, searching again, I found the wiki page again, which also lists the regression.
For now, I've installed the extension posted with the bug report, which will add the "visited" attribute, making the following work:
#content tab:not([visited])