Since master template name is not the same as database name, which is shown in the "open application" dialog, there is no easy way to find and open in desinger the template wich is responsible for application's design. The technology for searching is already in place - it is been used when selecting "application -> refresh design". I would imaging the right-click action for opening the maister-template in designer, if designer is installed. It would bring up the dialog for selecting a server to perform the search on, with the administeration server of the database preset, or if none is set with the  server the database is actual reside on.