If you have the admin area secured with SSL, mine is sitewide, several features of the proofread dont work.
The inital proofread works fine and underlines words. But if you try to use Explain which makes a remote request Firefox blocks this by default without making an exception.
Here is the error.
Blocked loading mixed active content "http://service.afterthedeadline.com/info.slp?text=has+been+tested&tags=VBZ%2FVBN%2FVBN&engine=3&theme=tinymce&ver=358-24485"
If you just changed this to https://service.afterthedeadline.com/info.slp that should fix it.
Otherwise you have to grant exception everytime you load the page. but only after you have tried to use Explain. Before this you cant add exception because no resource without https has been loaded yet.
Should be a simple fix.