The second part seems to be fixed, but the first part is still happening in (I think) Alpha 5 (0.9.4.540).

Also, because of Plyxon's behavior to replace *all* tabs with spaces, I can't actually use this program. I have a codebase that is shared with other people and replacing all tabs with spaces would not go over well. I hope that this is just an "early alpha" problem and that normal support for tab characters will be added. Until then I'm happily using PL/SQL Developer.