When ArgoUML starts, then it shows an empty class diagram on which you can add various objects. ArgoUML works according the following principles:
The file operations save and open handle one
project at a
project corresponds to a
model plus diagram information,
i.e. everything you can edit within the ArgoUML window.
model may contain many
objects (ModelElements) which
form the complete UML description
of the system you are describing.
All ModelElements might be present on a diagram,
but this is not required.
that is stored in ArgoUML is
independent of the contents of the diagrams.
This may be explained by the possibility
to generate programming code from the
model - you
do not need any diagrams for this.
project also contains
all diagram information, i.e.
the shapes (presentation) used
to represent the various UML ModelElements,
their location, color, etc.
Some ModelElements appear on multiple diagrams,
some on one or none.
Hence, saving and opening projects
retains all this information.
There is a way to only save the
though, which is by the menu
"Tools" -> "Export as XMI...".
This may be usefull e.g.
when generating programming code
with an external tool
that understands XMI.