I had this problem as well. Though from my experience is that it is on the panel.
It's more a case of the icon which should be showing, isn't loading up. So you are left with an invisible area of a couple of pixels wide which I could click. (Only noticeable by a slightly bigger gap than between other icons)
When I clicked the invisible bit and started wireless the icon then appeared as wireless and after stopping it, it showed the usual image.
I had this problem as well. Though from my experience is that it is on the panel.
It's more a case of the icon which should be showing, isn't loading up. So you are left with an invisible area of a couple of pixels wide which I could click. (Only noticeable by a slightly bigger gap than between other icons)
When I clicked the invisible bit and started wireless the icon then appeared as wireless and after stopping it, it showed the usual image.