Flux fully supports Full Screen in Lion. To turn on Full Screen, click the icon in the top right of the window. Please note that Full Screen mode in Flux required Mac OS X 10.7 (Lion) and will not work in any older version.
When using the Full Screen mode, you can also enable the Embedded Site Manager, so it easy to access all the assets of your site without leaving the Full Screen view. You can toggle this option with the Toggle Site Manager menu item in the View menu.
The Embedded Site Manager supports drag and drop, so you can easily drag images and other assets to your page.
To leave Full Screen mode, move the mouse pointer to the top right of the screen, and click the blue button shown in the image above..