> In immediate mode, none of that matters. You don't have a parallel widget tree. No, instead, you need to have your entire dataset in memory, and potentially

> In immediate mode, none of that matters. You don't have a parallel widget tree. No, instead, you need to have your entire dataset in memory, and potentially rebuild your whole tree on every update. This causes quite a lot of problems for out-of-core datasets - you end up needing to maintain proxies for things like items in scrollable lists that aren't loaded into memory yet.