First of all let me say nice program. I do have a couple of suggestions that I feel would make it even better.

When I click on the name of the fence it would be really good if it collapsed down to just the name or an icon. 
Then when I clicked the name or icon (or perhaps when I pass the mouse over it) it would restore the fence to its
original size. This would make it really useful for net-tops.

If I click on a parshley obscured fence it brings it to the foreground

The option to have the fence expand to show all the icons it contains. Ether when i pass the mouse over a fence or
when I click on it not sure which would word better.

A nicer looking scroll bar.

What do you think?