The problem is with the svg icons. Other icon themes have no problems. If I rename gnome-netstatus-[0-9]*.svn out of the way and rebuild the icon cache, there is no extra space around the signal strength icon, but the icon still doesn't look like it's supposed to: it is scaled with no regard to proportion (see the attached image).
BTW, I have cropped the two 24x24 icons to 12x24; I don't know if extra margins would appear if I hadn't cropped them.
The problem is with the svg icons. Other icon themes have no problems. If I rename gnome-netstatus -[0-9]* .svn out of the way and rebuild the icon cache, there is no extra space around the signal strength icon, but the icon still doesn't look like it's supposed to: it is scaled with no regard to proportion (see the attached image).
BTW, I have cropped the two 24x24 icons to 12x24; I don't know if extra margins would appear if I hadn't cropped them.