Thank you for the clarification.
I exported the XSD’s and then cleared the all xdmf_id values and the ‘cloning’ worked.
I tell you the way to clone a foxml display-
The problem comes because the system tries to duplicate a key in table:
export the foxml xsd , the modify---- e.g. xdis_title="Conference Poster" to xdis_title="cloneConference Poster"
then replacve all: xsdmf_id=" to ---e.g. xsdmf_id="22
save the file and import it . YouŽll see this works.
I hope find and modify this bug in the near future.