In an Domino application that I was working on, I had code behind an action hotspot that saved the current document and composed a new document. When I had to modify the design of the form to include an input validation formula, the existing code behind the action hotspot didn't activate the validation formula. Here's how I solved my problem.
Code: OLD CODE: @Command([FileSave]); @Command([Compose]; "formname")
NEW CODE: @If( @Command([FileSave]); @Command([Compose]; "formname"); "" )