If a Fence is at the top of the screen, its label automatically moves to the bottom of the fence, which is nice.  However, the top of the fence is still associated with the "move fence" function.  The label side is ALSO associated with the "move fence" function, as you'd expect.  Unless a user chooses to lock his fences (adding a couple steps to the process of expanding a fence to add an icon), this can be annoying.  For example, if I have a mostly-maximized window (that's generally how I work, which is why my most frequently used icons line the edges of my screen), I can't click on desktop icons (again, unless I lock the fences, which I've done as a workaround).  This problem does NOT exist for fences which aren't at the top of the screen.  All icons are completely clickable on such fences.

I've included an example below, showing the top portion of my desktop, with the unclickable area highlighted in red. (This screenshot may not look like it's using fences, but if you look closely, you'll see that their opacity is set to _almost_ zero. I have it set to show fence labels only when a fence is highlighted.