Small theme fix

themes/default/bottom-active.png

themes/default/bottom-active.svg

themes/default/bottom-inactive.png

themes/default/bottom-inactive.svg

themes/default/bottom-left-active.png

themes/default/bottom-left-active.svg

themes/default/bottom-left-inactive.png

themes/default/bottom-left-inactive.svg

themes/default/bottom-right-active.png

themes/default/bottom-right-active.svg

themes/default/bottom-right-inactive.png

themes/default/bottom-right-inactive.svg

themes/default/close-active.png

themes/default/close-active.svg

themes/default/close-inactive.png

themes/default/close-inactive.svg

themes/default/close-prelight.png

themes/default/close-prelight.svg

themes/default/close-pressed.png

themes/default/close-pressed.svg