It's hard to replace your SyntaxEditor in my application :(
Your wpf ribbon have a full support of RTL : it also reverse the application layout.
But let me propose a classification about an Arabic language support:
1) Full: also application interface is RTL
2) UI Language: application have usual LTR look but all text is in Arabic
3) Basic: application is not localized but the input can be in Arabic
4) Mininmal: the input is in Unicode, so I can copy past Arabic text.
5) None: the application dosn't support unicode.
I've made some test and I've seen that, your SyntaxEditor is at level 4, but it have only two wrong behaviours for level 3 (which is what developers usually ask):
I can write text in arabic and the typed word flow RTL, with only the caret in the wrong position, but:
- when I type a space char the next word is on the right ( RTL is at word but not at sentence level).
- when a text is selected the higlight mess up the caracters ( only the hilighted chars are writtren LTR )
If you fix this two issue users of your component can do the remainig works and have application that can be selled to many other customers.