# vim /usr/share/gnome-shell/theme/gnome-shell.css
/* PopupMenu */
.popup-menu-boxpointer,
.candidate-popup-boxpointer {
-arrow-border-radius: 8px;
-arrow-background-color: rgba(0,0,0,0.9); # Panel popup menu background and transparency
-arrow-border-width: 1px; # Panel popup menu border width
-arrow-border-color: black;
-arrow-base: 24px;
-arrow-rise: 11px;