WPF RichTextBox无缝TextBoxes作为InlineUIContainers

I'm attempting to "Tokenize" text inside of a WPF RichTextBox control. Whenever the user types a ";", the text before it is placed into a new TextBox contained within an InlineUiContainer. This allows the text to be programmatically different, and yet still be editable. I'm attempting to "Tokenize" text inside of a W