If you have a page with some different of elements on it
like

• some images with lightbox
• a video
• elements which can be unfolded
• etc.

The usage of these elements could be tracked via Custom Events
see #472

To make your website better it would be not only interesting which elements/functions are used, but on the other site:
which elements/functions are never or only very rarely used.

This may have several reasons:

• they are not visible to the user (design problem)
• there could be a technical problem (technical problem: maybe only in some browsers)
• no one needs them (content problem)
  ...

To find these elements it would be very helpful to have the possibility to find & show them in an automatic way via "Invers Custom Event tracking"

one way may be

• a possibility to mark elements (their events) as "being watched because they should be used"
• to call all events of this marked group per page to say "hello - I do exist" to piwik (some kind of crawler)
• compare these events with the statistics piwik have from the Custom event tracking
• show a list per page with the events never or only rarely used (maybe with a customizable filter..)

What do you think?