When I test topics with the different Connections editors (CKEditor, Textbox.io and TinyMCE), I always used multiple users in my test environment, installed the editor selector ear and then gave each of the test users a different editor. That’s easy with the different j2ee roles, but I always had to use multiple browsers or sandboxes to see them next to each other.
Several people told me that installing the Editors is not described very well in the IBM Connections documentation. So i decided to write down the steps I used to deploy the editors. Hope it helps.
Check Installation on ephox: http://docs.ephox.com/display/EphoxForIBMConnections/Installing+Textbox.io+Services