move subtask

It should work to do cut and paste, but you can also hide enough tasks (maybe use search) so that there is blank area in the task viewer, and then you can drag and drop the task onto the blank area and it will be removed from its parent.

I am afraid it does not work.
To make it simple now I am just trying to detach the subtask from his parent task within the same category.

drag&drop
By drag & drop, I does not work.
When I get the subtask with the pointer and drag it, a little hand appears and while dragging the name of the subtask is shown, as soon I a stop moving I only see the hand, no more information about the subtask, and as soon as I drop in a blank NON forbiden area, the subtask desapears, it can not be found even with search. U recover it with undo.

By cut&paste neither.
When I cut the subtask, it desapears and the parent gets highlighted.
If I use paste from the menu, it does nothing. Clicking in the blank area does not show left-button menu options.
I can only use paste as subitem to recover it as a subtask of any other task.

Using version 1.3.20 portable on windows 7 x 64.

I am not clear: you are talking about tasks in the task viewer or categories in the category viewer?

Tasks are items you check with dates and such. Categories are tags.
If you use composite tasks, they can be functionally like categories, you could call them categories, but to be clear we call them parent tasks because they can have dates and such too and be marked complete (unlike Category tags).

Now, I apologize for the confusion, but I am guessing that cut and paste is WORKING but you are hiding the task. Perhaps you have a category tag checked so that you are seeing only items with that category. Then when you move a subtask out from a parent, if the parent has the category, then you will see everything from it. If the subtask does not have the category tagged, then it will be hidden unless you mark it with the category or you uncheck the category (thus showing everything).

Try: View>Filter>Clear All Filters.

Also, drag and drop is a little confusing. If you drop just above or below another task, it marks a dependency/prerequisite relationship between the two tasks, to move a task out from a parent, it has to be dragged to a completely empty area. However, cut and paste should do this also, and I guess your problem is the filtering, as I said above.

Please let me know if this answers things.

OK.

The idea of categories and task was clear. My task and subtask(or subitem) are categorized.

The problem was that I was supposing that just because I was dragging/pasting to the window's pane of the selected (checked) category It was going to put it there automatically. It seemed logic to me they'd do it, don't know.

As you said I found all tasks I moved in the "general view" without category.

Thanks so much Aaron !

Sounds like you want to vote for this request:
http://taskcoach.uservoice.com/forums/26465-desktop-version-windows-linux-mac-of-task-coach/suggestions/680683-drag-and-drop-tasks-into-categories

Also, you can mark tasks with categories with contextual-menu click, with the action menu, and in each task's editor.
Plus, if you are currently filtering by particular categories, and new task you make will start with those categories checked.

Cheers