We recently upgraded one of our instances from 3.1 to 4.1.7 and I can't delete a plugin macro in the rich text editor, so it displays on the page.
We have some macros that have been disabled - were free and now require a license, and we don't need them. The TOC ones display a box with Edit Remove so I can get rid of them.
This is also an adaptavist one, according to firebug, but there's no way to delete it. In Edit mode, there's no indication that anything is there at all so no way to remove it.