Highlight resources you don't have in trade screen

Hi,

the new trade screen is very usefull as you can easily see what reasource are available to sell by other players.

Why don't highlight the resources you have on the list of tradable resources of other players? 

As-is I need to "manually" check if a resource (expecialy luxury one) is already mine or not and of course buy resources you don't have is stronger than duplicate them (stack bonus are less powerfull than base one)