Isolate button only can isolate selected objects and can’t separate selected parts (faces or elements) of selected objects. In editable poly we have some tools for display select parts but it doesn’t have suitable accessibility for fast modeling.
In UV Editor we have a button “Display Only Selected Polygons” for isolate selected faces between UV unwrapping. Something like this button with a related hotkey will be helpful for faster modeling when we are working on any editable modeling tool set like edit poly, mesh, NURBS and spline.
