If you install an app while KDE is running, it isn't getting picked up in the menus; should rerun desktop-create-kmenu. It would be fine to just run desktop-create-kmenu if a change is detected in /usr/share/applications /etc/X11/applnk or /usr/share/applnk I think. (Those are the important directories things are merged from.)
it's already done in current current kdebase.
Maybe this is how it is supposed to work, but I don't get the menu and kicker updates until I log out and back into KDE. This is with kdebase-3.0.3-11. If this is the expected behavior, then please close out.
It should update immediately.
it's a bug in kdelibs and fixed now in kdelibs-3.1-9.