Bug using Quote

@Alexander Ebert

If you press Quote, and also on the little black box and select insert all, you post text along with the text to the previous post??? (see image)
members on my forum writes that they have the problem with all browser and also mobile.

and I have tested it here

Quote markup test

Quote from Alexander Ebert

I'm sorry, but I struggle to understand which steps I have to take in order to reproduce this?

Have a look here------> Movie