Hi, Jet, I have a workaround until they fix the bug.
I create a new category with the name of the one I want to move the grade items around in. I usually add a 2 to it. Then I can Select all the items and move them to the new category. After confirming that they are all there in the new category with a 2 in the name, and that they are no longer in the original category, I delete the empty category.
Next, I rename the new category with the 2 on it to the original name so that the items will show up in the gradebook because they are linked to the original grade item. Now you can move them around using the technique that was previously posted. I had to do it for each category.