If in creative you take a container with items and put it into and item frame and then middle or control middle click that item frame the container you get will be empty
If in creative you take a container with items and put it into and item frame and then middle or control middle click that item frame the container you get will be empty
I wasn't able to replicate this behavior, even with furnaces (all 3 types) and a shulker box. After middle clicking I was given the proper item with it's NBT data.
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