Side Box Question

[Bruce1952]

Hi everyone,

I have a quick question regarding the Categories side box on my site http://www.outdoorking.com that somebody might be able to help me with.

I am attaching a picture from another site which explains what I am looking for but unable to find in the add onns here. What I want to achieve is similar to the picture attached is that the main categories are listed in the side box without the drop down box and then as the customer scrolls down the list all the sub categories show (similar to windows explorer) and they then click on the area that they are interested in.

If someone can direct me to the correct add on it would be appreciated as I am unable to locate it.