How do I make the HTML toolbar display when an HTML file is active?

Right-click on the HTMLBar button on the Plug-ins toolbar, and select Properties on the menu (or right click on the Plug-ins toolbar, click Customize Plug-ins…, select HTMLBar and click Properties). Check the Automatically display the HTML Bar for selected configurations check box. The HTML toolbar will be displayed when a file with a configuration that is enabled in the list is active.