Build 14942, now has a Hide app list in Start menu setting (All settings/Personalization/Start). This has no effect if the Use Start full screen setting is turned On.
I was looking through all the threads I had posted in and saw this thread. It looks like it's now called Show app list in Start menu. I don't know which build this change was made on, but again, this setting will have no effect if you have Use Start full screen set to On.