What is the best way to indicate a web page element has right click functionality? [duplicate]

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Normally on the web, a right mouse click makes a browser menu appear.
I am building a rich web application and most UI elements will have context menus with applicable actions on right click.

What would be the best way to let the user know that special functionality is available via a right click:

  • for a particular UI element (a panel or a button for example)
  • for most of the elements on the page?