Version:           4.5 (using KDE 4.5.0) 
OS:                Linux

On Ubuntu 10.04 LTS, I installed the kubuntu-desktop package so I could use KDE and GNOME on the same virtual machine. I chose gdm for the display manager when it asked me. KDE was working flawless, but it was a bit slow (The VM had 512MB RAM). I wanted to use KDE 4.5.0 (which is the latest official release) so I started KPackageKit and added ppa:kubuntu-ppa/backports to the list of software sources. Going to the updates tab (I did refresh it), there were about 100 updates and about 42 blocked updates (there were none before I added the PPA). I installed them all and then restarted the VM properly. Logging into KDE, all of the controls looked ugly. I open System Settings and then double clicked on Application Appearance. CDE was selected. When I clicked on the combobox, Oxygen was not there anymore. Yes, the KDE version said 4.5.0 and so did a lot of the other KDE applications. The VM software I was using is VirtualBox 3.2.8.

Reproducible: Always

Steps to Reproduce:
(Make sure you're trying Kubuntu 10.04 or Ubuntu 10.04 with the kubuntu-desktop package installed)
1. Open KPackageKit.
2. Goto the software sources tab.
3. Add ppa:kubuntu-ppa/backports to the list of software sources.
4. Close the software sources window.
5. Click Reload when it prompts you.
6. Goto the updates tab.
7. Click Refresh.
8. Select all of the updates and click Apply.
9. Wait for it to finish.
10. Logout.
11. Restart the OS.
12. Login to KDE.

Actual Results:  
The Oxygen option is no longer in the menu and CDE is automatically selected.

Expected Results:  
Oxygen would still be there and everything would be fine.

OS: Linux (i686) release 2.6.32-24-generic
Compiler: cc
Variant: Ubuntu 10.04 LTS
RAM: 512MB
VM: VirtualBox 3.2.8
Virtual hard drive: 8GB