Simple Request: Single Uncollapsed Catagory Displayed

[Gwydion Frost]

I want to have all Catagories displayed in collapsed modes, except either a single preassigned default or the user's single choice.

Only ONE catagory can be open at a time. The User simply clicks and picks.

How can I make it happen?  

[Hood15]

You would have to add onto the javascript function for the collapse and expand and make it do a foreach based on the div names.

[Gwydion Frost]

Thank you, but it might as well have been Greek.

<------ Visual designer, not programmer.