I found now with the 2.x branch version that changes made to a CSS injector file via an external text will not display or refresh when you navigate to the editor of the same CSS injector in the admin console. The CSS however does get executed. This use to work in the 1.x branch.

The other thing too is if you are in the visual editor and then press save, any changes that you had made via the external text editor will be lost.

I may be in the minority here but I generally like to make edits to my CSS injector files via an external text editor. I found it more efficient, particularly now that there is no "Save and Continue" in the 2.x branch version.