Comment # 6 on bug 920792 from ��kos Sz��ts

I'm sorry for the very late answer.

I did some strace'ing and found the following:

1.) With qt5ct being set to Breeze (
        ~/.config/qt5ct/qt5ct.conf:
        [Appearance]
        custom_palette=false
        icon_theme=breeze
        style=Breeze
  ):

The System Settings application first looks at this file and loads the style
defined inside (currently, Breeze). The Breeze icon theme
(/usr/share/icons/breeze/index.theme) contains a line which explicitly states
that it inherits from the hicolor icon theme (Inherits=hicolor) i.e. if an icon
cannot be found among the Breeze ones, the application should look at among the
hicolor ones next.

In my ���Most icons are fixed��� screenshot the selected element's icon is
���preferences-desktop-keyboard-shortcut.svg��� according to the SystemSettings. It
cannot be found neither in Breeze, nor in hicolor. Interestingly, it is
contained only in ���gnome��� and ���Adwaita���, Oxygent doesn't contain it either.
Although gnome and Adwaita contain with name
���preferences-desktop-keyboard-shortcut_s_��� and not with ���shortcut���.

2.) When directory ~/.config/qt5ct is not present then all the icons are
missing. This is because ksystemsettings doesn't even try to load a single .svg
file.

I'll attach the two strace files I worked from.