I remodeled my bathroom 12 years ago and installed a new American Standard single handle shower control (the kind that looks sort of like a tongue depressor). I noticed recently that it was dripping from the shower head (about one drop every nine seconds) and so I replaced the ceramic cartridge with a new one (American Standard PN 023529-007A, cartridge kit including seals). Much to my chagrin, the dripping continues at about the same rate, even with the new cartridge and seals. Can you suggest anything else I might check that could be causing this leak?