Yes, there is a little combo box. The popup shows all the table occurrences and the text field inside auto completes. When select something or press return after typing, the plugin will pass that text to the search in relation graph:
Coming soon for FileMaker 13 and 14 with MBS Plugin 5.4.
The FileMaker conference here is great and people have a lot of excellent ideas. We have a long list of things to improve in MBS Plugin in the next years.
So far we got a couple of improvements including a search field for scripts, a configurable highlight color in script editor and Elliptic Curve Sign and Verify. We'll see what happens tomorrow here in Hamburg!