The TinyMCE full screen button has been disabled by default. To enable it:
1.) Open /admin/com/templates/editor.tpl
2.) Around line 20 add "fullscreen" to theme_advanced_buttons3. For example: theme_advanced_buttons3 : "fullscreen",
You can change which line the button shows on by putting "fullscreen" in the other _advanced_button lines.
You may need to clear your cache and/or logout of the application for the changes to take effect.
