Dificulties in modifying or duplicating a view I'm using drupal 8 (it seems to me exact version is 8.1.8) as CMS. 
I created many views, and I would like to modify them o to duplicate those views.
But, mainly after I set a contextual filter, is not possible to modify the view. 

And I 'm experiencing troubles too in duplicate a view and then modify the parameters. 

Is there any know issue about those difficulties?
Instead of creating multiple views, have you considered using additional displays from the base view instead? That way they can share common configuration, but you can do things like apply a contextual filter to just certain displays.