XnView Software

There is, currently, no easy ability to sort the categories. To adjust their order.
You can move them to a different parent category, but not (easily) adjust the order in which they appear under that parent category. (or in the "root")
So if you take a category tree like this: …then you can move BBB to be a child of DDD, or child of CCC, or to not have a parent …but there is no option to put it under CCC, nor to put FFF at the top or between AAA and DDD.
Before I registered on the forum, I e-mailed about this, and was told that they are always sorted alphabetically, but…
1. That is clearly not true. Plenty of the categories in my tree, are in places they shouldn't be, according to alphabetical order.
2. Above I stated that it isn't possible to easily adjust the order.
Not that it isn't possible
…because I have found that it IS, technically, possibly. By deleting and then re-creates sub-categories (I did this in the Categories Filter-panel. I don't know if the same would work in the Categories-panel), one can get whatever order that one likes.
It is, however, very annoying, tedious, awkward, and cumbersome.
Especially if there are any images with those categories. (as would be the norm)

Edit: I have confirmed that this is true of the Categories-panel as well as the Categories Filter-panel: When adding a subcategory, they will often be placed at the bottom, regardless of alphabetical order. This can be used to sort the categories, in the order one wants them to be …though it is a very tedious method. Simply being able to move them about, as one wants, would be far better. (with the option to sort them alphabetically, perhaps?)

Edit 2: Actually, the new category appears to get places where "New Category" would fit in, alphabetically …but as long as one gives the categories names with, say, an "A" in front of the desired name, and then rename them, to remove the "A", it still works.

Just to show that, no, the categories are not always sorted alphabetically, and you can absolutely get them to be non-alphabetical. To get them into whatever order you want …though it is very annoying, tedious, awkward, and cumbersome. (Just made a few random new ones. Not the best possible example, but should be enough. )

I have found, that closing and restarting XnView, does actually appear to result in the categories being sorted alphabetically.
…so they tend to get created and moved about, such that they won't be in alphabetical order, but will later be in alphabetical order.
Regrettably.

That's a bug if sorting is applied only once XnView has been restarted.

+1 - I support your request for a user-defined/custom sorting. Alphabetical sorting of categories might not be wanted by all users so there should be an option to allow for manual sorting and disable automatic sorting.

helmut wrote: Mon May 02, 2022 9:58 pm+1 - I support your request for a user-defined/custom sorting. Alphabetical sorting of categories might not be wanted by all users so there should be an option to allow for manual sorting and disable automatic sorting.

…and the ability, when manually sorting, for alphabetical sorting of just the sub-categories under one parent. (or of just those at the root of the category-tree)

zarlan wrote: Sun May 01, 2022 5:23 pm I have found, that closing and restarting XnView, does actually appear to result in the categories being sorted alphabetically.
…so they tend to get created and moved about, such that they won't be in alphabetical order, but will later be in alphabetical order.
Regrettably.

You have that after adding custom categories?

Custom categories? Aren't all categories, custom categories?
If you mean categories, aside from those that are there by default…
I deleted almost all of the categories that are there in XnView, by default. (I think I only kept "photographs" and "videos"? Possibly one or two others?)
I have quite a big tree of categories (and I've only started. It'll be a lot more), and will have to rearrange and reorganize some parts, think about how to build/organize the tree…