I’m not going to make a detailed post, just a screen-shot based overview of the new features you can expect in KDE 4.5.
There was a lot of talk in the beginning about why Kickoff and Lancelot are not like the classic menu – and don’t have popups. Although I still don’t consider cascading popups to be good, liblancelot supports them. After a large amount of polishing, the feature is ready to be exposed in the menu itself. It is considered experimental, but it works quite well.
How to activate: Configure Lancelot Menu > Applications > Open popups for subcategories
This feature is not yet enabled for the Shelf applet (ex Lancelot Parts) but it still may find its way into it for 4.5.