Issue
In current user tests we found out users expect some kind of "drag and drop" feature to transfer text from the "show changes" side on the left to the editor box on the right. It seemed they would choose copy and paste as a workaround.
Solution
Offer a way to transfer (e.g. drag and drop) text from the changes side to the editor.
Note
We are looking for a technical solution here to keep the UI free from instructions which usually stress the user if there are too many of them. If there is no technical solution we need to make it more clear "copy and paste" is the actually wanted action.