Shell – RHEL 7, GNOME shell – decrease desktop icon size

Or a workaround I've found to do that:

Open (Unity/Gnome file manager) While holding CTRL, scroll with mouse scroll up/down to increase/decrease the icon sizes of the "Files" Amazingly enough this will change the size of the desktop icons as well.

Open ~/.config/plasma-org.kde.plasma.desktop-appletsrc with a text editor.

Find every line starting with extraItems=

Add another line iconSize=3 below each of those.

Save the edited file and exit.

After a reboot the icons should have a much higher limit of size when adjusting the height of the panel.