Repro steps for Firefox 26-28:

1. Paste the following HTML into Atto:

   before<br><table><caption>capt</caption>

   <thead><tr><th scope="col">a<br></th>

   <th scope="col">b<br></th>

   <th scope="col">c</th>

   </tr></thead><tbody><tr><td>d</td>

   <td>e</td>

   <td>f</td>

   </tr><tr><td>g</td>

   <td>h</td>

   <td>i</td>

   </tr></tbody></table>

   between<br><p><br></p>

2. Expand the Atto toolbar such that the Table button is visible.
3. Click one of the table cells.
4. Click such that the caret is positioned at the end of the last word.
   • Observe that the Table button is shaded as though you're inside a table.