Within the product setup screen from description (tabs) I get this error when trying to add an image or a link. Happened on upgrade to 5.65

Web.config registration missing!
 The Telerik dialogs require a HttpHandler registration in the web.config file. Please, use the control's Smart Tag to add the handler automatically, or see the help for more information: Controls > RadEditor > Dialogs > Introduction

All other html/editor on site work ok. Just within smith cart product add

7.0.1

I wasn't able to replicate a Telerik error but I am also testing on a new version of DNN than you. I am using 7.1.2 and you are running a pretty early release of DNN 7 so it's quite possible the error you are getting is DNN version specific.

Looks like the formatting issue is isolated to the FireFox browser and only exists in some of the admin screens. I have added this to our Bug Tracker system for our programmers to address and we will reply to this thread as soon as an update is available.

Thanks!