The de-canonizing of previous books, comics and more was pretty much inevitable with a Star Wars sequel trilogy on the way, but some fans were still surprised when it was announced everything outside of the six core movies and TV show The Clone Wars would be no longer part of official continuity. There's been a lot of debate among Star Wars fans since the Mouse House took over the franchise, with perhaps the earliest and most long-standing controversy being the decision to get rid of the Expanded Universe.
The new Star Wars canon created after Disney purchased Lucasfilm and started a new movie trilogy helped clear up some serious confusion regarding Jedi Master Ki-Adi-Mundi.
