I upgraded my project from 5.1.1 to 5.3.3 and it broke my canvas in menu. There is nothing visible in editor unless I check override sorting or add a new element but that are just ugly workarounds it should be working just as it used to in previous version. Interestingly, everything works just fine in game. I don’t want to redo all my ui just to use newer version. What’s wrong with unity :////
Read this thread, submit a bug report. A similar issue was fixed for 5.1, this could be the same or similar bug.