To hide the toolbar, simply select 'Hide Toolbar' under the 'View' option in the main menu, located near the top of the SpreadsheetLIVE user interface. Once it is hidden, the option will change to 'Show Toolbar', if you decide that it's preferable to see the toolbar. The toolbar is highlighted below.
Image 1 - The 'Hide Toolbar' option in the 'View' menu and the toolbar highlighted in the interface.