Unable to organize a blog's subcategory

It is very easy to create a blog subcategory:

• 'Add a category' + select from 'Subcategory of:'
• Use the 'add-category' tool of a specific category

The problem is when:

• you want to move the subcategory under another category;
• transform the subcategory into a category.

Right now, editing a subcategory allows to change only its name.
A solution is to display also the 'Subcategory of' select in the editing step.

Another solution would be to allow drag&drop.

The only solution is to go to that subcategory and change it's parent to Blog.Categories or Blog.[DesiredCategory].