Rust behind shower bar

[MandK]

The other day after using the shower I noticed a rusty water seep coming from behind the lower shower bar attaching point. I removed the screw cover to find trapped water stained with rust from steel screws. I removed the bar to clean things up. I reattached it, this time using a beding of sealant around the screw holes and stainless screws. I also filed a notch in the bottom of the screw cap to let water drain out. I am guessing it took this long for the water to seep out the bottom because until the rust particles filled the holes around the screws, it just seeped through the screw holes into the cavity behind the shower. No sealant was used at all. The covers slide off easily to take a look to see if you need to do this repair.