It also now uses an OSS library, HarfBuzz, to position the glyphs.
The kerning problem is well documented, e.g., see here:
http://forums.mozillazine.org/viewtopic.php?f=39&t=21588...
> Also, try right-clicking the back icon, rather than holding down the mouse button.
Sure, you can get the list either way, but why change from the widespread convention of having a down-arrow for a drop-down list as earlier versions did? The newer version is less discoverable, and making that sort of change without a good reason is just poor usability, pure and simple.
> And using the toolbar's Customize system to move Refresh and Stop and Home wherever you want them.
I hadn't even realised Firefox 4 still had such a Customize option until you mentioned it. To activate it, I have to navigate my mouse cursor to a region about 3-4px wide (on my 1920x1200 screen) between some of the areas on the bar, and right-click, even if the mouse cursor has already changed to the left-right arrow in some of those places. Once again, this is just poor usability (as is moving the buttons around in the first place when upgrading from an existing Firefox 3 installation that had them in a different place where they could still go).
Also, try right-clicking the back icon, rather than holding down the mouse button. And using the toolbar's Customize system to move Refresh and Stop and Home wherever you want them.