Basically, once you start editing a document in an embedded editor control, Notes expects you to save the document. Since this is the case, we can use this fact to make a simple addition to our embedded editor. Here's my approach.
Create a new action (via a button, link, whatever makes sense) to allow the user to cancel the edit transaction. Since Notes needs the document to be saved, add some computed for display (CFD) fields on the embedded editor form to hold the initial values of the fields you are exposing for editing. Set the value of the fields like this:
@If(@IsDocBeingLoaded; field_1; @ThisValue)
@If(@IsDocBeingLoaded; field_2; @ThisValue)
@If(@IsDocBeingLoaded; field_3; @ThisValue)
When the doc is opened in the embedded editor, these CFD fields will get set to the starting values of their corresponding fields. If you want to cancel the edit transaction, you just need to set the fields back to their initial values, then save the doc. Something like this:
This is an elegant way to handle a fairly common scenario when using embedded editors.