Bukkit

• Fix dupe bug when players attempt to drag items outside of the inventory window and then close the client
• Fixed invalid cost calculations being applied to users using the GUI screen to upgrade their backpacks.
• Fixed text alignments on GUI screen
• Implemented a prettier color background texture
• Fixed invalid backpack current size when in a shared world and attempting to upgrade it.

b129 also works with 1.5.x builds.

Be sure to read the overview page for more information on what stuff isn't quite finished.