Hi,
I have just migrated from Mandriva2011 KDE4.6 to Mageia2 KDE4.8.
During the first start of Mageia, I created a user account with the same login I was using so that I could keep all my KDE settings and other applications settings.
All went very well except all elements linked to the ROSA theme that are rather hardcoded in Mandriva2011 or Rosa distributions.
(it is possible to manually re-create some with deKorator and Elementary theme, desktop theme Elly, and a copy of the icons theme).

But even by selecting the Oxygen window theme (default in Mageia), I still have the following problem:
Buttons and display are not changed and remain somehow corrupted with a CDE theme type (rather old looking theme).
Ex:

Other new user accounts created from scratch in Mageia are looking ok:
Ex:

I cannot find in my .kde4 folder where to correct this. Could you help me fixing this?
Thank you!

try clearing your cache, should be done when you are not logged in /var/tmp/kdecache-user_name

also run kbuildsycoca4 --noincremental

Thanks for the help!
I have tried clearing the cache logged as antoher user, and the command:
It runs ok in root but with no effect on my problem.
When I run it logged with my account, I get the following error:

$ kbuildsycoca4 --noincremental
kbuildsycoca4 running...
kbuildsycoca4(14940) parseLayoutNode: The menu spec file contains a Layout or DefaultLayout tag without the mandatory Merge tag inside. Please fix your file.

I don't know if this is related, nor what to do...

That message - like virtually all from kbuildsycoca4 - can be safely ignored, it functions as a warning rather than an error.
You can check the output of "kde4-config --localprefix" to determine what should be used instead of ~/.kde4/ - it is likely to be ~/.kde/ instead.

One thing you could try removing is ~/.config/Trolltech.conf.

The ouput of kde4-config --localprefix is ~/.kde4/
double checked: there is no ~/.kde/ in my user home directory.
I removed ~/.config/Trolltech.conf, logged out and logged back in.
This file has been rebuilt (smaller size btw), but the result is still the same, non-KDE applications are still using this old default style.

But doing some more tests, I realized that I am confused between the choice made in KDE System settings / Application Appearance / Style , and the appearance of non-KDE applications.
With a new user, the appearance/style of non-KDE applications is similar to Oxygen but changing KDE System settings / Application Appearance / Style would actually never change non-KDE applications.
For colors, I see that there is a box in KDE System settings / Application Appearance / Colors to choose Apply colors to non-KDE4 applications which is working pretty well for firefox for instance.

So how is the equivalent of Application Appearance / Style for non-KDE applications defined? and how to change it?

Thanks again,

Ah. Non-KDE applications are usually written in Gtk 2 or 3. Try removing ~/.gtkrc-2.0 from your user - optionally copying that file from another user.

OK... I didn't manage to find anything in my ~/.* folders to correct the style, but I could do this by installing and using Gtk+ 2.0 Change Theme.
Thanks a lot for the hint, I am new to this .

It would be so nice, from a user perspective of course , to have all settings embeded in the KDE System settings, as it is possible for colors.
The only mention of this that I found in the KDE bug tracking system is Bug #302928 ("making GTK apps look native under KDE"). Could this be worth reporting?

So for now, I actually did not meet any KDE problem during this migration, this is really magic software

From what I know, there is a 3rd party module on kde-apps.org which allows one to set their Gtk theme.

Thanks for the info, when searching for it I found out that it is actually now part of KDE.
The name is kde-gtk-config.
It is available on the Mageia depots, so now I am using it instead of this gtk change theme..
So the settings appear as a new tab between Fonts and smileys in the Application Appearance windows.
This is better integrated.
Thanks again