I think that I am following protocol here, though I admit to being too rushed at the moment to check things thoroughly. Bear with me, please.
I am running a recently downloaded copy of Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1). One change I note is the per-tab clickable 'X' button to close each individual tab. As a user, I like this, but I recommend a change to the tabs bar related to this.
Recommendation: Add a separate clickable 'X' button outside of all tabs on the Tabs bar which, compatable with earlier behavior, closes the currently-active tab. Withoug this, I find myself often mistakenly clicking the 'X' button in the rightmost-displayed Tab bar item in an attempt to close the (different) currently-active tab.