Redmine

It also makes sense inside a project. I keep forgetting that I can't "move" an issue to another category. Move is the logical place to look for that.

No, the Category is an attribute of the ticket and is changeable in the Update pane, the Move action is really only intended for moving tickets from one project to another (which involves some more backend processing than "just" changing an attribute).

Anyway, Category is available for mass-editing in the issue list, so you could just select all the issues for which you want to change the category, right-click on an "empty" space of the selected issues and assign them a new Category.

The original use case that failed without this feature was as follows:

1. Have two projects A and B
2. Have many issues in each project, many categorized, many uncategorized.
3. Try to move a set of issues from project A (category 1) into project B (category 2).
4. Note to yourself that you can't assign category 2 on move at this point.

Since you can't assign the category on move, and I believe the category is only sticky if you have the same category in both projects, it's very easy to lose the issues you just moved in the morass of uncategorized issues in project B. Obviously you can go find all the issues and assign a category, but it's not always easy to find them when you have non-trivial numbers of issues.

There is a workaround of creating matching fake categories in each project before you do these moves, but this is obviously unintuitive.

Hopefully this clarifies the motivation for such a feature.

we just hit the same problem. it's VERY inconvenient to move hundreds of issues from 1 project to another (we're reorganizing our redmine categories structure).
a must-have step is "choose related categories":
src cat1 --> dest category1
........

+1