restart_interaction() called when ctc_position="fixed", why?

[Human Bolt Diary]

This seems to be causing a small "blink" effect on the click-to_continue icon whenever the user clicks to continue reading.

For reference: https://github.com/renpy/renpy/blob/c24 ... aracter.py

Inside the SlowDone class, restart_interaction() is called when the ctc_position is "fixed".
However, when the ctc_position is "nestled", restart_interaction() is not called.

I don't understand the use of restart_interaction() in this context. Why does the _ctc screen need to be restarted every time the text changes?