If you using the serializable cart mode, then the searching is actually quite limited, ID and Customer name are actually not supported but were not properly hidden (and I might have something to do with that). So the bug was fixed, but in a way of limiting the UI instead of providing the missing features, because it is not supported by the lower level
According to this bug:
The search function for searching Shopping carts should be fixed, but it still not works for me after updrag to 12.16.
Searching for an Id and nothing happens, the search result stays the same. And it is the same for all seach options when searching for shopping carts.
Maybe I'm missing something or the bug is still there?