examples: Add transparency to the rounded rectangle
examples: Add transparency to the rounded rectangle

Makes it a bit more fancy.

Distrotech/clutter,Distrotech/clutter,jigpu/clutter,Distrotech/clutter,GNOME/clutter,GNOME/clutter,jigpu/clutter,Distrotech/clutter,jigpu/clutter,Distrotech/clutter,GNOME/clutter,GNOME/clutter,GNOME/clutter,jigpu/clutter,jigpu/clutter,Distrotech/clutter,jigpu/clutter