My bad, I must have forgotten to update the documentation after I introduced the highlight functionality in the last update.
To fix this, doubleclick on the MouseSelectReply method to go to its definition in the OverriddenDemoDialogueWidget.
Then change its parameter type:
https://i.gyazo./b1ee31a0d2624976cdebfd57c96a88fa.png
Let me know if you encounter any other similar issues. Thanks for this report.