No Dashboard, no Editing, suddenly nothing when we login to site
C5 loads its header and editing interface within the theme code such as
Meaning if an extra or missing closing div tag (etc) could cause the c5 header/footer elements to be excluded rendering the c5 interface useless..
Granted that is only on front end, if you have issues in backend then I'm not sure....
If you can navigate to the dashboard page (http://concrete5.dev/index.php/dashboard/pages/themes... ) and activate another theme, you could see if editing controls come back and then you know its the theme.