Fragment references are resolved when you preview a form design or save it as a PDF file in LiveCycle Designer ES, LiveCycle Forms ES, or LiveCycle Output ES.
When you update a fragment, all form designs that reference the fragment reflect the changes when you open the form design in LiveCycle Designer ES. All form designs that are open in LiveCycle Designer ES are also updated.
Fragment references in PDF forms are resolved when you open or save the form design in LiveCycle Designer ES. If you update a referenced fragment after you save the PDF form, the old fragment is still visible when you view the PDF form in Acrobat. To update the fragment that is visible in the PDF form, you must resave the PDF form in LiveCycle Designer ES.
See also 

How fragment references are resolved