reverting r12185 from #3431

git-svn-id: http://svn.openlayers.org/branches/openlayers/2.11@12232 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer.js

@@ -349,11 +349,6 @@ OpenLayers.Layer = OpenLayers.Class({
             this.div.style.width = "100%";
             this.div.style.height = "100%";
             this.div.dir = "ltr";
-            if (this.opacity != null) {
-                OpenLayers.Util.modifyDOMElement(
-                    this.div, null, null, null, null, null, null, this.opacity
-                );
-            }
 
             this.events = new OpenLayers.Events(this, this.div, 
                                                 this.EVENT_TYPES);
@@ -1274,8 +1269,11 @@ OpenLayers.Layer = OpenLayers.Class({
     setOpacity: function(opacity) {
         if (opacity != this.opacity) {
             this.opacity = opacity;
-            OpenLayers.Util.modifyDOMElement(this.div, null, null, null, 
-                                             null, null, null, opacity);
+            for(var i=0, len=this.div.childNodes.length; i<len; ++i) {
+                var element = this.div.childNodes[i].firstChild;
+                OpenLayers.Util.modifyDOMElement(element, null, null, null, 
+                                                 null, null, null, opacity);
+            }
             if (this.map != null) {
                 this.map.events.triggerEvent("changelayer", {
                     layer: this,

lib/OpenLayers/Layer/Markers.js

@@ -60,6 +60,22 @@ OpenLayers.Layer.Markers = OpenLayers.Class(OpenLayers.Layer, {
         OpenLayers.Layer.prototype.destroy.apply(this, arguments);
     },
 
+    /**
+     * APIMethod: setOpacity
+     * Sets the opacity for all the markers.
+     * 
+     * Parameter:
+     * opacity - {Float}
+     */
+    setOpacity: function(opacity) {
+        if (opacity != this.opacity) {
+            this.opacity = opacity;
+            for (var i=0, len=this.markers.length; i<len; i++) {
+                this.markers[i].setOpacity(this.opacity);
+            }
+        }
+    },
+
     /** 
      * Method: moveTo
      *

lib/OpenLayers/Layer/WFS.js

@@ -590,5 +590,21 @@ OpenLayers.Layer.WFS = OpenLayers.Class(
         return extent;
     },
     
+    /** 
+     * APIMethod: setOpacity 
+     * Call the setOpacity method of the appropriate parent class to set the
+     *     opacity.  
+     * 
+     * Parameter: 
+     * opacity - {Float} 
+     */
+    setOpacity: function (opacity) {
+        if (this.vectorMode) {
+            OpenLayers.Layer.Vector.prototype.setOpacity.apply(this, [opacity]);
+        } else {
+            OpenLayers.Layer.Markers.prototype.setOpacity.apply(this, [opacity]);
+        }    
+    },
+
     CLASS_NAME: "OpenLayers.Layer.WFS"
 });