Just installed this, loving the whole "Move a fence, desktop icons move out of the way". I laughed. :]
One "issue" I noticed is when in the config, the "Keep fences spaced [X] pixels apart" resets to 0 when going back into the control panel. I confirm that when you set the value, close the control panel, the fences DO keep a distance apart. When you close, then go back into the control panel, it shows 0, however, unless you change that value, the fences DO maintain the previous setting.
Edit: Would be nice for the fences to also move as you're changing this value so you can see the change, and not have to manually re-adjust the positions later.