That might be nice. It can't be done, though. We just have to go to inventory and look through it, relying on our own flawed brains to spot the difference. Well, my flawed brain, and other brains in whichever states they may be. Still, that bit of lacking information is a minor thing, relative to other issues.
If you have faith in the higher powers, you might try suggesting it in
the ideas section. I'd suggest something similar to what's shown when plundering; vanishing numbers and icons, but that's not a function currently used on the GE map. If they do it at all, it'll probably end up something like indicators in the inventory. That seems to be all the rage at Inno's offices, at present, and they probably already have much of the necessary code for it implemented on the GE map. It's a simple suggestion, so they might do it, much to the agrivation of those who couldn't care less, and will then have even more frequent, unwanted flashing of the inventory icon.