Kpersonalizer problem

Hi all, I've got a little but nagging problem with Kpersonalizer. I've setup a Raspberry Pi with Raspbian (the latest Raspbian Stretch works very well on a 3 B+, by the way) and installed TDE from Slavek's repositories. Then I decided to rename the "Pi" user. Since that, every time I log in I get Kpersonalizer. If I don't run it, I get no icons on the desktop. If I do, some of my previous settings are kept, some are lost (colours, windows decorations). This certainly is a permission problem and dome file not being written, but where? Root works very well. I could (and possibly will) create a new user, but first I would like to understand what is not going right. Thierry