Dropping would pass the name of the ID to drop to the properties of the drop operator. This would then lookup the ID by name. With linking and/or library overrides, multiple IDs of the same name and type may exist, which is why the session UUID should be used instead. All operators used for dropping support this now and the drop code passes the session UUID instead of the name. Also see917c096be6and8f79fa9c67. Some drop operators were already using the session UUIDs. This converts the remaining ones. The "name" property is kept working as before, since some scripts use this. Side-effect: The "Name" property won't show up in the Adjust Last Operation anymore, which was the case for some of these operators, and its value won't be remembered over multiple executions of the operator. Both were not at all useful from what I can tell, and I doubt this was done intentionally.