Subproperties are displayed twice when binding a property to a widget

A document type has a complex property "Adress", with subproperties (all string) street, zipnumber, city.

On the creation layout of the docuemt type, I drop the Adress property and edit the content.If I click on "edit" to change the bound field (on one of the subproperties), the tree displays twice the subproperties.