Assorted features

This is an assortment of feature-demonstrations.

Features:

• The big red arrow is an <area> with display:none set. It won't hilight.
• The star uses the metadata plugin to adjust how it looks
• The right-hand square uses the metadata plugin to always be visible, to have no border, and to have a greenish fill
• The lower-left square is linked to the star using groupBy. When you mouse over it the star will hilight as well.
• Mouse over this to trigger a hilight from an external element!
• Click this to toggle whether or not the star will hilight