It seems that updating to the latest WP (4.2.1) broke the feature to edit texts with the frontend editor. When you click on the edit icon, the editor appears, but the text field wil remain empty.
I updated to Agile 3.3.
Are you referring to the frontend editor of Visual Composer? I always recommend using the backend editor for visual composer since I found the visual composer frontend editor to be a little buggy. The theme has been tested well with the backend editor and should work fine.