Services overlay should be uninstalled when it's no longer needed
I will note that you can "clear" the overlay if you for some reason want to keep it installed without the memory/performance cost.
But that's really only useful if you for some reason still want to get e.g. mouse events. Otherwise, I guess uninstalling it is probably the best plan.
<rdar://problem/17929146>
This was fixed as a side effect of http://trac.webkit.org/changeset/172382.