It depends on how you inserted it. Files inserted with the "store a reference" option specified can be opened by double clicking the container field if inserted with the insert file option.
Files inserted by other means or without that option can be opened with the Export Field Contents operation--but be careful. If users need to open the file, modify it and then save those changes, the changes won't be there for the next person unless you re-insert the editied copy back into the container field.
I've done exactly as you describe and it does not seem to be working. I am using the "Insert File" option and selecting the Word document file with the "store a reference" box check. I can see that the file is in the field but double clicking on it does not open it up. Any suggetions?
What operating system are you using?
What options did you select for this container field on the Inspector's data tab--optimized for pictures or interactive content?
This only works if optimized for pictures is specified.
That got it. I was optimized for interactive content and not pictures.