bitbake: hob: disable layer drag and drop outside the containing widget

[YOCTO #6008]
(Bitbake rev: 0f7b6a03c64292983d2cc715e5e5badb1cdc5cae)

Signed-off-by: Cristiana Voicu <cristiana.voicu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/ui/crumbs/hig/layerselectiondialog.py

@@ -132,12 +132,13 @@ class LayerSelectionDialog (CrumbsDialog):
         tree_selection.set_mode(gtk.SELECTION_SINGLE)
 
         # Allow enable drag and drop of rows including row move
+        dnd_internal_target = ''
+        dnd_targets = [(dnd_internal_target, gtk.TARGET_SAME_WIDGET, 0)]
         layer_tv.enable_model_drag_source( gtk.gdk.BUTTON1_MASK,
-            self.TARGETS,
-            gtk.gdk.ACTION_DEFAULT|
+            dnd_targets,
+            gtk.gdk.ACTION_MOVE)
+        layer_tv.enable_model_drag_dest(dnd_targets,
             gtk.gdk.ACTION_MOVE)
-        layer_tv.enable_model_drag_dest(self.TARGETS,
-            gtk.gdk.ACTION_DEFAULT)
         layer_tv.connect("drag_data_get", self.drag_data_get_cb)
         layer_tv.connect("drag_data_received", self.drag_data_received_cb)