Hi,
I have just today installed Firefox 3 and Zotero 1.0.6. (previously running FF 2 x and Zotero 1.0.4)
Most things appear to work fine, but I have lost the vertical scroll bar on the tag selector window. ("Collections" still has its scroll bar) This is possibly because Zotero now shows all the automatic tags, (big heaps!) but extending the window to its full height and dragging the edge as far to the right as possible to maximize the size, still does not return the visibility of the scroll bar.
What to do?

Not sure how to send the screenshot?

I have just sent an email with the screenshot attached.
I think this might be an issue with some of the auto tags lacking proper separators - there seem to be some groups of imported tags separated by semicolons which are not being read as separate fields. Long fields may be pushing the whole tag selector column so that it and the surrounding tags effectively disappear under the central column.
I am guessing if I could drag the whole widow to the right I would find the scroll bar again. It certainly reappears when there are only short tags in the window.
That's my best guess anyway.
Right now I am doing a labourious manual job of going through every item and checking the length of the tags appended to it, and breaking them up when I find a long one. So far only up to the "K's "
See what you make of the screenshot.

Hmm,
I just checked each of my 'collections" for tag selector scroll bar problems and they all work except two. Both of these were originally imported from EndNote. (I have retained my imports from EndNote in separate collections. ) Why one of the three imports works and the other two don't would probably require me to recollect what I was doing in early Feb of this year which is when I installed Zotero and added them. Memory does not stretch that far.
However it could also be a function of slightly different labels in each of the imports. I have noticed in the past that when using the EndNote imports in Zotero some of the fields were a bit odd, probably because I added a couple of extra fields in EndNote and renamed some when I was using it But it must also have something to do with auto tags as this was not a problem in Zotero 1.0.4
Your turn to guess?

I am having similar problems with tags. The box for tags, as you know, has always been located in the bottom left corner of the screen. After I downloaded version 1.0.6 of Zotero, the scrollbar that always appeared at the left-hand side of the tag box suddenly disappeared. Without a scrollbar, it is now impossible for me to view all of my tags beyond the first two or three lines. There is a related problem. Apparently the scrollbar in previous versions was acting as a barrier to the tags, preventing them from spilling past the margins of the tag box. In addition, the tags were displayed or aligned with full justification. Now that the scrollbar has vanished, the tags are extending to an undetermined point several inches past the default left-hand side of the tag box. Even if I pull the barrier between the tag box and the middle column as far as I can to the left, I am unable to reach the far left edge of the left-most tags that are partially displayed in the tag box. It also appears, though I can't be sure, that the full justification in the tag box has been traded in for a flush left, ragged right justification. The reason I think this is happening is because the unequal spacing that used to occur between tags in full justification has now apparently been replaced by equidistant spacing between tags in the tag box. I hope you can bring back the scroll bar, restore the full justification of tags, and keep all of the tags displayed within the left- and right-hand boundaries of the tag box.

Or, if you can't see the tag selector menu because it's beyond the right edge, go to about:config in the Firefox address bar, search for extensions.zotero.automaticTags, double-click to set that to false, then open a new Firefox window.

PhDinHistory said
"It would be nice to have a way to identify the really long tags so that I could shorten them."
I heartily second that!
Only after I got the scroll bar back could I go through the tags with any ease to shorten them. Before that I could not see past letter E. Perhaps a separate 'edit ' window as for Notes or similar that displayed each tag on one line would assist. One line to a tag would make picking up problem lengths easy.

In addition to the Edit window suggested above, breaking up tags on import is the obvious solution, but there might be times when you actually want a longish tag. Allowing the edge of the tag column to kern and /or wrap tags would permit this.

Thanks for the scroll-wheel tip too.
I believe there is a sex difference between men (scrollers) and women (non-scrollers) so I tend not to think about the use of the scroll-wheel as an option.