Transparent background for XFCE desktop icon texts

For semi-transparent background of XFCE desktop icon texts, put this into your ~/.gtkrc-2.0 file:

style "xfdesktop-icon-view" {
  ## opacity of text background (0 - 255, 0 = transparent)
  XfdesktopIconView::label-alpha = 50
  XfdesktopIconView::selected-label-alpha = 150
}
widget_class "*XfdesktopIconView*" style "xfdesktop-icon-view"