When running "kcmshel kdm" as user and clicking in button "Get New Themes" the theme doesnt get installed.

Its only possible to install a new theme, using the same procedure, by clicking in button "Get New Themes" and select to install a new theme, only if running it as root.

Reproducible: Always

Steps to Reproduce:
Run as user "kcmshel kdm", click in button  "Get New Themes", select a theme and click in button "install", the button then appears as "Uninstall", i close that window and in main KDM window im not prompted to enter root password, also the new theme doesnt appears listed.
I clock in the OK button and continues without asking root password and closes KDM window.

Actual Results:  
Already described.

Expected Results:  
After selecting the new theme (from the new window themes) should prompt the user about the root password to get the new theme installed.