What I am trying to do is:
I include a hidden field (not shown) in properties dialog, that field
used to point to a keyword in my external BibTeX database.
When users double click on object, a prop dialog appears and shows
various props including a button. Clicking on the button will invoke
function call to readin BibTex file, search for the keyword, and a new
dialog appears. That window contains information about the BibTeX entry,
searched using the keyword. I wish to have multiple keys, pointing to
various entries, just like UML class has mutiple atts. The difference is
that I need to interact with my external files, and do NOT save
information within Dia. I just attach keys to object.
Hope this make things a little bit clearer.
Thanks
You should not update the original one; if you did, you'd slip under the
undo mechanism (which, for stdprop objects, works using lists of property
values).
If your object's state can be completely described using a list of property
values (which, as a stdprop object, should be the case), then it should not
matter that the specific object instance changed. What are you trying to do
exactly?