Board Thread:Editor Board/@comment-26391060-20131101164532/@comment-6697950-20131101173153

When in editing mode, check the right side of the editor and you will see a list of categories. If you hover over a category, you will see two icons pop up: a pencil for editing the name of the category and a trash bin icon for deleting the category.

If you are using an iPad or another mobile device, the icons may not always work, but I know of a roundabout way to force the categories into source code.