Hypothetical situation - how to track a movie with the newly improved(?) IMDB webpage

Suppose I buy a DVD and want to add it to one of my existing IMDB lists, most of which I have created to represent different criteria.  So I open up IMDB and type in the name of the movie and the page opens up. I used to be able to click on the little checkmark or + sign, whatever, that was in the upper left-hand corner, and, lo and behold, I may have found that I already had this title listed on three of my lists, which, in short, means that I already owned it! Since I have almost 5000 movies in my home library, I often forget which ones I already have so I sometimes purchase movies somewhere that I already own but don't remember. Now I may be faced with the decision of whether to keep duplicates, dispose of the movie, or do something else with it. The only problem I have now is that I have no simple way of discovering if a new movie is already included on one or more of my lists, since the little checkmark or + sign does not appear in the new and improved(?) version. Maybe I just am not knowledgeable enough about how to get around in IMDB, but I haven't been able to reconcile the new revision to suit my purpose.

Can any member help me with this or am I just SOL?