hi, i discovered fences recently and really like it, thanx for this cool tool 
But i think there is one small internal setup missing, fences are clearly z-ordered\layered on the desktop. Fences being made on top of each others, the last made take dropped icons in priority. No matter, but it seems there is no way to change this order, so fences have to be made in the good order at creation time which do not integrate/fitt very well with the "interactively create when needed" fences interface.
For example, the really cool "exclude fence/icon from quick hide" feature loose a lot being unable to create a fence which stand under the"unhiden" already created fences. I have no idea on the way this ordering could be altered, but one over simplified way would be to make fences created while in the quick hide mode being under hiden fences (but on top of fences excluded from quick hide), another way would be a "create new fence under the others here" button at creation time, which will place the new fence just under the "deeper" fence crossed by the new one geometry, this would allow to create fences anywhere in the fences "stack" even if this is not a really clear way to do this while fences stacking is not explicitly showed to the user.
a save layout feature, even if it does not save icons positions is really missing too.
Finally a style/color setup for each fence would be great even if i understand that this can be a largely more complex problem playing with the ms windows transparency composition setup.
hope this help, waiting for something like that, i will keep creating a small set of already created fences sstack before/under the others 
thanx again and sorry for my poor english 