Stick mousemove event to element' context

Signed-off-by: Igor Vaynberg <igor.vaynberg@gmail.com>

Author: creage

select2.js

@@ -139,13 +139,14 @@
      *
      * filters out mouse events that occur when mouse is stationary but
      * the elements under the pointer are scrolled.
-     */
-    $(document).delegate("*", "mousemove", function (e) {
-        $(document).data("select2-lastpos", {x: e.pageX, y: e.pageY});
-    });
+     */    
     function installFilteredMouseMove(element) {
+    		var context = $(element[0].document);
+    		context.on("mousemove", function (e) {
+		        context.data("select2-lastpos", {x: e.pageX, y: e.pageY});
+		    });
         element.bind("mousemove", function (e) {
-            var lastpos = $(document).data("select2-lastpos");
+            var lastpos = context.data("select2-lastpos");
             if (lastpos === undefined || lastpos.x !== e.pageX || lastpos.y !== e.pageY) {
                 $(e.target).trigger("mousemove-filtered", e);
             }