Hi Christophe,
There is a way to unset Show Relation Title for a link by setting it's GraphicalProperty ShowName to None.
for( Object obj : app.getSelectedGraphElements().toList())
{
if(obj instanceof IRPGraphElement)
{
IRPGraphElement gEle = (IRPGraphElement) obj;
gEle.setGraphicalProperty("ShowName","None");
}
}
------------------------------
Ruchit Solanki
------------------------------