Following behavior:

 

I set the property to false. When I copy and paste a selected area of an HTML-Site, everything works fine.

 

But for example, if I select an HTML-Code in an Editor OR (where I was point to this problem) from the source-Code view of w3-Validator, the HTML-Code will be pasted into the editor...

Also the <font>-Tags won't be removed.

 

Any ideas???