I am currently having a very strange problem with the KDE widget style.
The problem consists in that the widget styles are not respected. All windows appear with something that looks like the default GTK style (I don't know the name). If I change the style in
systemsettings, the appearance for currently open windows change, but new windows continue to appear with the wrong style.
This does not seem to be affected by which style I choose in the settings (I have tested with Oxygen, Plastique and Skulpture. Also, I have confirmed that opening applications with the style set by the command line (such as
ksysguard --style oxygen) does work.
I have not found any information whatsoever in the Internet about this (probably because all the results are about KDE-GTK engines, which this is not about.
I don't know if this has to do with any of it, but this is happening ever since upgrading from 13.04 to 13.10.
EDIT: To clarify, here goes screenshots:
If I simply open any KDE program, I get this (rename file dialog from a Dolphin instance), which is not the Oxygen style I set it to:
If I go to System Settings->Application Appearance->Style, set any option (i.e. changing an option and immediately reverting it, just so the Apply button will be enabled, I get the following appearance (correct style). This also happens when I launch a program with the style set by command line (