create a script with debug.setmemorycategory("horsemanure").
go to studio settings and show every hidden object in the datamodel
press play
go to Stats.Memory.PerformanceStats.PlaceScriptMemory, here you will only see the default memory categories from 0 to 256. But not horsemanure.
To be clear it still finds its way to the dev console, just not reachable via Stats
Thank you for filing this. Our Performance Diagnostics widget in Studio is currently under review and we are looking at ways to redesign it and improve its functionality while reflecting all the data that is available in the DevConsole.
In light of this I don’t have a prediction for when this will be addressed but we’re aware of the issues.