Xfce launchers don't have blue underline shadows

Created by: tonypaulic

Current code:

.xfce4-panel button#launcher-arrow:hover, .xfce4-panel button#launcher-arrow + button.toggle:hover {
  box-shadow: none;
}

leaves inconsistent missing blue underline (box shadow) for launchers in Xfce. Changing the above to:

.xfce4-panel button#launcher-arrow:hover, .xfce4-panel button#launcher-arrow + button.toggle:hover {
  box-shadow: inset 0 -2px #315bef;
}

creates a consistent look/feel on the panel.