In some operators that previously allowed duplicating the selected data-block,
the operator would not be available now. 2250b5cefe split the "new" operators
into "new" and "delete" to allow clearly differentiating between the two. But I
apparently didn't amend all affected data-block selectors to use the added
"duplicate" operators.
I went over all operators that were split now and made sure all affected
data-block selectors are updated.