Required 

fh: 

The tool bar container is placed directly under the menu bar and should be the same width as the window, as well as similar height to the menu bar. 

Recommended 

fi: 

If you use a tool bar in your application, then you should provide a status line in the same primary window as the tool bar. 

This status line should provide immediate feedback to the user as to the purpose of the button that the mouse is currently over or that has the keyboard focus. When the arrow is over a tool bar icon, the status line should display a brief definition of what the icon represents or what will happen when the user clicks the icon. 

Recommended 

fj: 

You may provide labels under tool bar icons. These labels should serve to explain the purpose of the icon.