Unlink result in fragmental <a>

[Garry Yao]

Reproducing Procedures

1. Open the replace by class example page;
2. Make the following selection;

   <p>
   	<strong>bo[ld</strong> and lin]k</p>
   

3. Open link dialog to add a link;
4. Make a new collapsed selection as following and click 'Unlink';

   <p>
   	<strong>bo<a href="http://example.com">ld</a></strong><a href="http://example.com"> and ^lin</a>k</p>
   

• Actual Result:

  <p>
  	<strong>bo<a href="http://example.com">ld</a></strong> and link</p>
  

• Expected Result:

  <p>
  	<strong>bold</strong> and link</p>
  

[Garry Yao]

Correct the description to clarify the problem.