Here’s a tip from highly respected Marin County FileMaker developer, Ted Fehlhaber:
Finding and Opening the Relationship Dialog
Anyone whose tried working with a crowded Relationships Graph has run into the problem of finding the right relationships icon (those little boxes between Table Occurrences). Once found, it can be difficult to select and open the right one.
Here’s the secret: If you select a TO that has only one relationship in a particular direction and hit the arrow key in that same direction, the first hop will select the Relationship icon. From there, Cmd-O (Mac) or Cntrl-O (PC) will open up that Relationship dialog. No more clicking around to try to select the right one.