In the RadEditor demo, first set "NEW LINES AS" to "Divs".
Then, in the editor content area just above the "Destinations" table, Type in three lines:
If you then toggle to the HTML tab, you will see that the Comment1 line is (incorrectly) bracketed by a <p> tag while the Comment2 and Comment3 lines are (correctly) bracketed by <div> tags.
Next, go back to the Design tab and position yourself at the beginning of the Comment3 line then click the [Insert Paragraph] button.
In the newly inserted "paragraph" type "Comment2b".
If you then toggle to the HTML tab you will see that Comment2b is incorrectly bracketed by a <div> tag.