The "vanilla flavored" wall switch from x10.com, the "WS-467", comes without local dimming capability: Though you can dim it from a remote controller, you can't dim it by hand by pressing its button. Strangely, it requires MORE components for them to make it WITHOUT local dimming capability. Shorting across the extra components "restores" local dimming capability to the switch.
Step 1: Disassemble the switch
see my project titled "disassemble an x10 wall switch"
Step 2: Short two pads on the circuit board with a solder blob
Step 3: Reassemble the switch
see my project titled "reassemble an x10 wall switch"