Hi,
I'm just trying to see what plugin, or config, I may be missing. I can see the same issue reproduced here: http://ckeditor.com/demo#standard
In standard, if you select the text "Apollo11" notice the "Increase Indent" is greyed out and not available. This is the same for my CKEditor (which is based on the CK Builder)
Next, flip to http://ckeditor.com/demo#full (another tab on the same page). In this instance you can apply indent to the "h1" and "p" elements or any elements. This behaviour is great and is what I would want for my CKEditor.
Any thoughts on how to enable this- maybe there is a plugin behind the scenes?