Simplifying logic that returns undefined when root is invisible.

lib/OpenLayers/Renderer/Canvas.js

@@ -788,10 +788,7 @@ OpenLayers.Renderer.Canvas = OpenLayers.Class(OpenLayers.Renderer, {
     getFeatureIdFromEvent: function(evt) {
         var featureId, feature;
         
-        // if the drawing canvas isn't visible, return undefined.
-        if (this.root.style.display === "none") { return feature; }
-        
-        if (this.hitDetection) {
+        if (this.hitDetection && this.root.style.display !== "none") {
             // this dragging check should go in the feature handler
             if (!this.map.dragging) {
                 var xy = evt.xy;