How do I add an action to a file of a given mime-type?
The simplest way is to run File > New... > Module Development > Action which creates an action for you and registers it in your layer.xml.
- On the first tab, choose Conditionally Enabled action and select DataObject as the cookie class.
- On the second tab, check File Type Context Menu Item and choose the MIME type and position.
You can use text/html, text/x-java, text/x-ant+xml, text/x-jsp, image/png, etc.