@cpennington Sorry,  I do not understand, what do you proposing. If I add javascript code in tab's js/html, it goes somewhere, now it belongs to window.TabsEditingDescriptorModel. Don proposed move TabsEditingDescriptorModel to CMS.models. I agree that " All of the javascript in codemirror-edit.html is initialization code that I'd expect to only get called when the editor is actually needed". But those functions from tab need to be put somewhere before being invoked.