The IDE fails to rename files. I can right-click on any file in a project, select rename, and see the file's name get wrapped with a text-entry box. I can type whatever I like in that box, but pressing enter does nothing: the textbox persists until another window takes focus, at which point the rename is cancelled.
Manually renaming the files using finder seems to lead to worse errors.
I'm on El Capitan 10.11.2 (15C50).