If there are not just alphabetic characters in the filename of a color-scheme, (like in most of the color-schemes from kde.org, for example 161377-Retro.colors) system-settings produce an error: QFile::copy: Empty or null file name and qt4-applications (like clementine) don't change the color! Deleting the numbers in the color-scheme filename helps. Reproducible: Always Steps to Reproduce: 1. Download color-scheme from kde.org 2. Check, if there is a number in the filename 3. If yes, select and apply the color-scheme Actual Results: qt4-applications don't change the color. Expected Results: qt4-application should change colors, too
I found out, that it is somewhat more complicated. Sometimes numbers in the filename do work and sometimes schemes with only alphabetical filenames don't work. The filehandling is somehow screwed up. Anyway: When the system-settings (started from the shell) reports QFile::copy: Empty or null file name the colors don't change in qt4 applications.
AFAICT, the problem seems to occur when the file name doesn't match the colorscheme name. E.g. the colorscheme "Arc Dark" installs a file "Ark Dark.colors", this will be successfully migrated to KDE4. "Diokai" OTOH installs "173965-Diokai.colors", the migration fails because kcm_colors tries to copy "Diokai.colors". In other words, the file name has to be the same as the colorscheme name (that's specified inside the .colors file) + ".colors" for this to work, if it is different it fails.
*** This bug has been marked as a duplicate of bug 353071 ***