Subform can see only icon on workspace?Why?

I received a memo which embedded a form with subform. When I open it, I can only see the form without subform.The memo sent from a database which include the design of the form and subform.

Once I open the database, i.e. the database icon is on workspace, I can see the subform in the memo when open the memo.

I tried to open the memo from different computer. Only the database icon on workspace, I can see subform in the memo.

No clue why like that?

If I send the memo which include embedded form with subform to many users, I can’t request the users open the database icon on workspace first.

How to solve it?

Subject: Subform can see only icon on workspace?Why?

Nobody knows?!