A) did you remove the plastic film covering the screen when you got the unit? Quite often people don't and the film will be the cause.
B) Let it sit and dry out on its own. Then as suggested use a bead of silicone sealant around the top edge where the black body of the control panel meets the side of the kettle. Run the bead around the sides maybe 3/4 of the way down. Don't seal the whole thing though or it won't be able to dry out if for some reason more moisture happens to get it.
Yeah, looks like I removed them film already. I only brew about once or twice a month so the foundry usually has two to three weeks to sit and dry (sits in the basement with dehumidfier).
I called Anvil this morning and talked with one of the guys in tech support. Super helpful. He explained the control panel is attached with two screws only accessible from the bottom of the unit -- you can get to them after the base is off. He said it's a pain-in-the-neck to take apart but is the only way. He mentioned the silicone too so looks like that's the way to go.
Thanks for the reminders. I've been careful not to slop stuff over the screen and have only had a couple near misses with boil-overs (distilled water in a spray bottle works nice for taming those). Not sure how the moisture got in there. Tech support guy said something about humidity and the same thing happening with thermometers but I didn't quite follow. The spigot was super loose once and left a puddle of distilled water on the floor, but that was long after the problem started. Maybe I had a slow leak into the heating element area causing the moisture to get in there, I dunno. Probably know more once I get it apart.
That's great that the manufacturer is an active part of the user community. Thanks for passing on the info everyone!