When we moved from the CFM builds over to the Mach-O builds for Mac OS X, a few things broke. The most visible of the problems we didn't get fixed for Mozilla 1.3 was XPInstall which is used to install mozdev add-ons and other extensions. Because XPInstall was broken in unknown ways, we decided to disable it for Mozilla 1.3. That also disabled theme install for Mac Mozilla.
Well, I just verified that this is all working again and should be in pretty good shape for Mozilla 1.4 Alpha, which is due sometime late this week. Thanks to Sean for staying on top of this problem and getting us the fixes (bugs 186088 and 195109.)
