Hello!
The "new" Item Condition drop-down you see is to comply with eBay's new policy. They will start "enforcing" the policy on new and existing listings next month.
It doesn't replace all the Custom Item Specifics, just the "condition", so you will still need to input the other specifics you have for your item.
Even though you may have already stated "new with tags" in your Custom Item Specifics, you will still need to select that from the new drop-down menu. It's an eBay thing. Frustrating, I know.