Also on every tablet NOT made by lenovo, there's just plain a "disable taskbar" option. So why would anyone be asking about this.
The closest to people asking about this are all Samsung users who say they fixed a problem similar to this with the "Good Lock" app. But that is Samsung exclusive?
I do some checks with adb shell settings list (https://gist.github.com/mcclure/47341511a2b91a1e64eb8a61b2f9ac4a) I find two settings in the "system" namespace that look germane but aren't it, and three mystery settings in the "secure" namespace