This tip is so easy, but is often forgotten.

When creating a Notes application with documents in a parent/child relationship, often times you would like to have a link from the child document back to the parent document. This is obvious when you're talking about a discussion thread - you want a way to get back to the parent.

All you have to do is create a computed for display text field on your child document. Call it whatever you want (Link or whatever), and the field value should be $Ref (no quotes - just as it is shown here).

When Notes displays the child document to the user, it will recognize that this field is a special field and turn it into a document link to the current document's parent. Note that even though it's a text field, a link will be displayed. And since it's computed for display, nothing extra will be stored in the document.

This field will work in both the Notes client and on a web browser (both will show a document link that can be clicked to open up the parent).