there is an inconsistency in icon location within xfce4 modules.  upon creating a desktop program launcher, one can select an icon from a window displaying icon thumbnails and different locations to choose an icon.  when an attempt is made to create a program launcher for the panel, however, the icon selection method is limited to a short generic list and a file finder dialog.  the desktop launcher creator's icon finder also has a quick search feature, which is lacking in the program launcher creator for the panel.  this icon finder with icon folders already listed and search feature should be the default icon finding applect across all xfce4/gnome-gtk interfaces.