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I have two eBay accounts, and only my older account gives me the option of adding an item directly to a custom list. In the newer account I can only add to my Watch List. I can move an item from the Watch List to a custom list, but if I remove the item from the Watch List, it is also removed from the custom list.
You should still be able to see all your custom lists by starting on your Watch List page and clicking on the large Watchlist heading to reveal a drop-down menu of your custom lists.
