I only find this feature useful if you have positioning enabled for everything. That is how I initially implemented this.
Either we assign positions for everything or use automatic positioning for everything.
This abortion of a situation where half of your stuff is positioned and half automatically positioned is a much more severe issue in the product I think we should fix first. Its causing confusion and is a nightmare to explain.
Personally I think users should select a site setting if they want to enable category positions. We can hint users at the site setting from the category edit page.
Then completely disable this drag and drop stuff AND disable the “position” box in category edit, unless “manual_category_ordering” is true.
Also, regarding these position numbers.
Say my order is 1,2,3,4,5 … now I want to move 5 between 1 and 2 … how can I do that? I guess our engine needs to be smart enough to shift everything forward if you set something to 1 and that spot is taken.