GNOME Shell throws the following warning message:
'St-WARNING **: Too many values for border-radius property.'
Was fixed with just remove the last '0' on the 'border-radius'
property in the '.tile-preview-left.on-primary' class on both files:
gnome-shell.css and gnome-shell-high-contrast.css.
https://bugzilla.gnome.org/show_bug.cgi?id=744900