The framework doesn’t allow to use the same view or window more than once in the repository browser. But in you example the view is assigned to a window and to a viewset.
In order to do this, the view BP_ADDR/ContactWorkAddrEF is assigned to the window:

and then this window is used via a component usage in this viewset:That means which each usage definition you can again use a window and assign it within the repository editor to another object. With every usage definition, a new instance of the component controller is created. If you want to avoid this, you can use the reference statement:
So BP_ADDR usage creates a new instance of this component, but with usage Dupl, you can use the windows again, but with the same controller instances as the BP_ADDR usages.
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