Problem with the new version, I've reverted for live use but here are the details:
I leave the Right Action bar active but empty, basically because I use a bar on the right hand side of the screen for various useful but not emergency things (spare totems for different healing spells, hotkeys for resist pots (not health/mana)) and find that if I track a quest it overlaps unless I leave that action bar up to force the text away from the right hand edge of the screen. BT4 (and BT3 before it) omitted the empty bar from the Next/Previous action bar rotation, going straight from Bar 2 to Bar 4. Now there's a blank bar (Bar 3) in the rotation even though it's disabled in BT4.
If this garbled explanation is insufficient, let me know and I'll post a screenie with the newer version installed.