For those of you using Delicious Bookmarks with Firefox, beware of that the latest version of the add-on (2.0.58) may break your tab navigation functionality.

Symptoms:

1. CTRL+PG_DOWN (and CTRL+PG_UP) behaved very funny. Instead of setting focus on the next tab, it sets focus on the tab next to the next tab. If I had exactly two tabs, C+PD/PU would always set focus on the tab that currently has the focus, i.e. nothing really happens.
2. Opening new tabs at the wrong tab order. Always to the right of the last tab.
3. Closing tabs sets focus on the wrong tab. Always on the first tab.

I am running FF 2.0.0.14 on Ubuntu Gutsy with roughly 30 add-ons enabled. I am way too lazy trying finding out if this issue only happens when certain add-ons are installed/enabled. Unless someone, who is serious in tracking this issue, needs me doing so.

Reverting Delicious Bookmarks to 1.5.44 (avaiable here) resolved the problem.

The last two symptoms described here might have something to do with Tab Mix Plus (I am using 0.3.6). I’ve reported this issue in a review on Firefox Add-ons.