To auto scroll this list just click in the list and start typing the category name. As you type the scroll bar will move through the list until you find what you are looking for.

If the category name is not in the list then you can add it by hitting the Add button (or the Insert Key from your keyboard) and typing the name of the category to add. Spell Check is available when adding.

You can also type your search query into the field under the list and press the tab key.Always clear the field by using the backspace key before starting a new search.

Below is what the category list looks like: