This is the place where the modules of the editor appear. Usually they show additional information or add editing options for selected elements in the content:
- go to the demo and you will see that space is left in a similar fashion, then select some element and see how this gets populated with options.
- more information on the available modules
If you want to remove them, please follow this article: http://www.telerik.com/help/aspnet-ajax/editor_disablehidemodules.html
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