Introduced in Notes 8.5 the generic container framework made it possible for all of the different containers you will see shipped in Notes 8.5.1. A new extensibility element introduced in Notes 8.5.1 is custom actions. This extension allows for new actions to be contributed to an existing container. Meaning, you can now write custom actions that can be wired to for the Notes view, Document, Sympony Spreadsheet, or Web container. We use the Eclipse extension point model and its nothing more than implementing an extension and writing a little bit of Java code. This allows for additional actions to be contributed to core functionality through a new plugin – no template changing or editing. There will be a full “Introduction to Custom Actions” article released very soon but in the mean time you can see how it works by example in this new wiki entry.
The new tutorial uses a custom action to format a URL passed into the Yahoo BabelFish site to translate the text. The interesting thing about this tutorial is it shows how your action can be called from Live Text using basic text selection from a Notes document.
Referenced article is here.