I was hesitate to make this feature request. So I try to use the categories in every place [ top left corner, in category list and category dropdown] and really look into how i use. I find that it’d be nice if we have the categories dropdown on top left and the one we choose when creating post if they share the same order in categories page.
And further more, should we make the category on top left to be select2 instead of normal dropdown. I find select2 is really awesome and convenience.
Note that there are two orders of category, and this at least is intentional:
order for browsing topics
order for creating topic
In case #2, that should be ordered by size, aka number of topics in the category – you want people putting topics in the most common categories, not in random places.