What Is Wrong with This Keybinding?

Ahh, I didn't know you could build "macros" out of multiple keybindings ... I've tried rapidly selecting previous target then selecting next target to reset the subtargetting, but every once in a while something pops up on the contact list just then and the "next target" turns out to be something other than my original target.

A button that does both simultaneously would overcome that problem, but somehow I doubt it will work. It's worth a try, though.