To avoid that in the future, I've whipped up a quickie new addon, Visibly Distinct Shadow Crypt, which does pretty much exactly what it sounds like it does. 
There weren't any obvious choices for the Shadow Crypt entrance's new tile, so I wend with the pentagram-looking tile used for Mark of the Spellblaze's entrance; I'm open to suggestions for something better.And I'm not sure this could go into ZOmnibus, since it's not really amenable to being turned on or off by a game option. (Plus I think people might call it "protection from not paying attention", which would disqualify it from ZOmnibus Lite.
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