Summary

Confluence editor adds multiple <span> tags in the HTML code, when entries in a list are copied and pasted.
With each copy and paste operation the count of the span tags is doubled. This only happens in Firefox

Environment

• Firefox

Steps to Reproduce

1. Create a page. Enter the following:
   
2. Check the storage format. It would look something such as follows:

   <ul>
     <li>
       <span style="color: rgb(255,0,0);">one </span>
     </li>
     <li>
       <span style="color: rgb(255,0,0);">Two</span>
     </li>
   </ul>
   

3. Copy the line "Two" and create a new line such as follow:
   

Expected Results

1. Check the storage format. It would look something such as follows:

   <ul>
     <li>
       <span style="color: rgb(255,0,0);">one </span>
     </li>
     <li>
       <span style="color: rgb(255,0,0);">Two</span>
     </li>
     <li>
       <span style="color: rgb(255,0,0);">Two</span>
     </li>
   </ul>
   

Actual Results

1. Check the storage format. It look something such as follows:

   <ul>
     <li>
       <span style="color: rgb(255,0,0);">one </span>
     </li>
     <li>
       <span style="color: rgb(255,0,0);">Two</span>
     </li>
     <li>
       <span style="color: rgb(255,0,0);">
         <span style="color: rgb(255,0,0);">Two</span>
       </span>
     </li>
   </ul>
   

notice the <span style="color: rgb(255,0,0);"> is doubled

Notes

Happens in Firefox