We just switched to ArcGIS 10.3.1 from 10.2.2 at work. I've noticed that when I start to edit a feature, the Editor toolbar appears. I dock, customize it a bit, make and save some edits, and close the mxd. When I open the map again, the Editor toolbar is gone (Advanced Editing toolbar that I added remains). I start editing again, Editor toolbar pops up, minus the customization.
I can't find a setting to keep it as I added it. Never seen this behavior in previous versions of Arc. Is there a way to make it behave like previous versions?