apt question

Hello SuSE people, Should know the answer to this myself as I have been using apt for many years keeping all my SuSE distros right up to date. But I saw something tonight which made me suspicious and worries me. Did my update and then did the -s for upgrade. Apt offered to upgrade KDE to 3.5 and listed the packages to be upgraded. But then it said it would hold back kde base, multimedia, and a few others. They are presently 3.4.3 How can it upgrade KDE without those vital packages? And why is it holding those packages ? Am afraid if I had continued with the proposed upgrade I would have a terrible mess. Any ideas, explanations, etc. Bob S.