Couple of things would like to see better:
1) The biggest need for improvement is a more determinate handling of the actual characters in the current texture, enabling users to _toggle_ character sets, not just "add" them.
This would allow users to, in one-click, to add _or remove_ an entire character set. Any custom characters added manually, outside of selected character sets, could be simply grouped under a Custom Entries button to toggle.
Otherwise, just try to use this app 1 week after adding 10 character sets and see if you can remember which characters were added previously just by looking. GOOD LUCK!! :)
2) the Select a character set dialog is just terrible, heres why:
a) It uses odd, unconventional naming of character sets -- why not use the same as Apple? Thats what we users are used to, so dont try to be all different and special there, just do what users expect.
b) None of the character sets have any additional country information, so you basically have to become expert in all the various languages around the world to know that Japanese language characters are called something else in the app.
c) There are over 40 character set entries and yet theres no search? (!)
d) Entries are not sorted alphabetically; with that many entries, there needs to be _SOME_ form of organization to be useful.
So combine a) b), c) & d) and yeah GOOD LUCK finding what you need! As-is requires constant scrolling, trying to decipher the unconventional naming of character sets… Clearly the list needs work! :)
3) Last thing, though minor, the icons, color choices for the inspector views, and overall look & feel are just awful; what is this, Windows 3.1? Please update the appearance for this century, thanks :(
Other than those bits for improvement, good tool; gets the job done!