Rated 4 out of 5 stars
Very useful when needed. I used the add on for some time but the email displays became too overcrowded so I decided to uninstall it. But, nevertheless all my messages keep showing all hidden attachment despite the fact that the add on was removed. I do not know now how to stop this add on.
Turn it off the same way you turn it on...
View | Message Body As | Original HTML (or Simple HTML or Plain Text).