SelectFeature control can now select across multiple vector

layers when passed an array of layers instead of a single layer with 
the constructor. This changeset also introduces a new layer type, 
Layer.Vector.RootContainer, which will be set as the topmost layer by 
the SelectFeature control and collect the svg/vml/canvas roots of 
multiple vector layers. r=crschmidt (closes #1666)


git-svn-id: http://svn.openlayers.org/trunk/openlayers@9116 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer/WFS.js

@@ -392,6 +392,20 @@ OpenLayers.Layer.WFS = OpenLayers.Class(
         }
     },
     
+    /**
+     * Method: display
+     * Call the display method of the appropriate parent class. 
+     */
+    display: function() {
+        if(this.vectorMode) {
+            OpenLayers.Layer.Vector.prototype.display.apply(this, 
+                                                                arguments);
+        } else {
+            OpenLayers.Layer.Markers.prototype.display.apply(this, 
+                                                                 arguments);
+        }
+    },
+    
     /**
      * APIMethod: mergeNewParams
      * Modify parameters for the layer and redraw.