Preview in New Tab
Preview mode shows the site in a smaller window. I generally like to open a new tab to see the rendered page. Editors with limited exposure to Kentico don't always know that they can do this.
I thought it would be a good option to add the extra option to open a page in a new tab (via a rollover option that appears under the Preview button perhaps?).
This accomplishes 2 things: It provides a full site view of a page, and secondly, it provides the full display of the url that can be copied. I would find it useful to grab the url and send it to someone, for instance.
I don't work for Kentico but I'm pretty sure you can already do this. At least, on our website if you're logged into Kentico and then in the same browser, open a new tab and go to the live site, it will open it in Preview mode (a little blue bar appears saying you're in preview mode and you can cancel it).
Non-kentico users are different though.