Foreshadowing Tom's departure

After reading the end of The Glass Menagerie by Tennessee Williams, I realized that there were multiple occurrences of foreshadowing throughout the play.  The first example takes place when Tom walks onstage at the beginning of scene one.  "Tom enters, dressed as a merchant sailor...( p 1236)."  At first, I barely even noticed this minor detail.  However, later on in the play, Tom's dialogue explains the significance of this detail.  On page 1268, Tom reveals he has become a member of the Union of Merchant Seamen.  The nature of his uniform is then understood by the audience.  Together, both details foreshadow Tom leaving his family to be a merchant seaman.  Although he doesn't leave until after the events of the play, the reader/audience can infer that Tom will eventually leave.  Combined with his desire for adventure and his hatred of his job, Tom's departure at the end of the play is a logical fulfillment of all the earlier foreshadowing.