Thanks!
But why not to show <multiple values> when each object has different value? If value is same or only single object is selected, show current value? If property doesn't already exists tell this and notify new one will be created?
Why I am asking for this is because I had to modify or add property "targetAddress" for several shared resources. It was not shown in the main windows object properties even after setting advanced properties to show all and show empty properties. If it's not already there, it's not shown. This makes sense.
So I picked Add/Modify Wizard and used it for adding property. It took some time dig which objects had this propety and which did not. If wizard would show existing property/property doesn't exist, it would be quite fast way go through bunch of objects and check if there's need to modify or add property.