a #GtkWidget which should be a drag destination for palette
the flags that specify what actions GTK+ should take for drops on that widget
the #GtkToolPaletteDragTargets which the widget should support
the #GdkDragActions which the widget should suppport
Sets palette as drag source (see gtk.tool_palette.ToolPalette.setDragSource) and sets widget as a drag destination for drags from palette. See gtk.widget.Widget.dragDestSet.