The new 52 and the witness protection thing got retconned.
Also we literally saw her dead body. Tim was at her, probably open casket, funeral.
Bruce and y buried her. There are few deaths that are as definite as that one.
I'm fine with her staying dead. Jack should be brought back tho. And Dana too.
Yet the story where Dick finds them in witness protection is still canon.
We are yet to know exactly what the deal is because ideally they shouldn't be in WP in Rebirth.
Pulls: Batman, Detective Comics, SiKtC, Catwoman, Nightwing, Titans, Godzilla, Wonder Woman, Batman & Robin, Brave and the Bold, No/One, Kill your Darlings, and Deviant.
My runs: Batman #230-, and Detective #420-