Perhaps the most important thing to know about TopStyle is how the Active Style Definition
works. To change the active style definition, simply select from the definition dropdown
shown above the style inspector.
The active style definition determines which properties and values are displayed in the style inspector and style insight. For example, if you choose "Internet Explorer 3" from this dropdown, only properties and values that are understood by Microsoft Internet Explorer 3.x will be displayed.
To help you quickly locate problems, any properties in the current style sheet that aren't supported by the active style definition will be color-coded red.