Whatever theme I select, its settings are lost and plasma falls back to the standard theme (Oxygen?) as soon as I open a qt5 app. I had a look in ~/.config/kdeglobals and everything seems to be OK in there. Reproducible: Always Steps to Reproduce: 1. Open systemsettings, go to Themes 2. Choose a theme, click apply 3. New theme is correctly applied. 4. Close systemsettings. 5. Open a random qt5 app. 6. Theme of the opened app is not what I chose in systemsettings. 7. Open systemsettings again, you'll see that it has fallen back to a standard theme (Oxygen?). Manjaro stable, kernel 4.1.7, nvidia non-free drivers, plasma 5.4.1
The Bug : If you put a theme in the folder /home/user_name/.local/share/plasma/look-and-feel/my_theme following breeze as model, it appears in the system configuration > look and feel > workspace > look and feel but when you try to apply it, breeze is runing instead of the theme. The same occurs with the splash screen and the loginscreen (sddm). Remarks : But the following items, taken separately : the cursor theme into /home/user_name/.icons/ can be choosed in system configuration > lookandfeel > cursor theme OK the desktoptheme in /home/user_name/.local/plasma/desktoptheme/ can be choosed in system configuration > appearance > desktop theme OK the splash screen in /home/user_name/.local/plasma/look-and-feel/theme/contents/splash/ or /home/user_name/.local/ksplash (Bug 314912) Breeze is running instead the choosed theme. FAILED the colors in /home/user_name/.local/colorscheme/ can be choosed in configuration > colors OK the icon theme in /home/user_name/.local/icons/ can be choosed in system configuration > icons > icons OK the emoticons in home/user_name/.local/emoticons/ can be choosed in system configuration > icons > emoticons OK the decorations in /home/user_name/.local/kwin/decorations/ can be choosed in systemsettings >application appearance > window decorations OK The gtk theme OK The sddm theme in /home/user_name/.local/sddm/ can be choosed in workspace>stop-start>deconnect screen SDDM but when you choose it breeze runs instead of choosen theme. FAILED Proposal: I suppose that you should change the name of "default" for a theme. But you can specify that the default theme = Breeze except if there is a user choosed theme. If a part of theme doesn't exist it will be replaced by Breeze. The themes complete or not could be defined in the folder : /usr/share/plasma/look-and-feel/ with the scheme: /name_of_theme/ metadata.desktop (Model=Breeze, add in this model all possible choices, perhaps with explanation.) /contents/ defaults (Model=Breeze, /desktopswitcher/ /lockscreen/ /osd/ /runcommand/ /userswitcher/ /windowswitcher/ /shortcut to /usr/share/icons/folder_of_icons__theme/ named appicons /shortcut to /usr/share/icons/folder_of_cursor_theme/ named cursors /shortcut to /usr/share/emoticons/folder_of_emoticons_theme/ named emoticons /shortcut to /usr/share/sddm/ named loginmanager /previews/ with all previews screens named as what they are make for, except the general theme preview which names preview /shortcut to /usr/share/ksplash/folder_of_splash_theme/ named splash /shortcut to /usr/share/kwin/decorations/folder_of_decoration_theme/ named windowdecoration /shortcut to /usr/share/kstyle/themes/ named style /shortcut to /usr/share/themes/folder_of_gtk_theme/ named gtkstyle /shortcut to /usr/share/plasma/desktoptheme/folder_of_desktoptheme/ named desktoptheme Shortcuts are to avoid to forget possible part of the theme. It is just a proposition.
This KCM has been effectively replaced with plasmathemeexplorer in plasma-sdk. If your bug still remains please roepen it there.