This post is an instructional post for using the Quote feature.
The grey box with M_Barne’s Username and short sentence is a result of my highlighting the sentence, which produces a small grey box that says “Quote”. Click that box and the system will take that highlighted sentence and populate the text editor with it. Then you can type your response to that particular quoted sentence.
(By the way, some users may be hiding that preview pane that displays on the right side of your computer screen by default. Toggle it back on to see exactly what your post will look like.