Merge pull request select2#1722 from yonjah/master

dropdown repostion fix when previous postion changes container position

Author: ivaynberg

select2.js

@@ -1130,7 +1130,7 @@ the specific language governing permissions and limitations under the Apache Lic
 
         // abstract
         positionDropdown: function() {
-            var $dropdown = this.dropdown,
+            var $dropdown = this.dropdown.hide(),
                 offset = this.container.offset(),
                 height = this.container.outerHeight(false),
                 width = this.container.outerWidth(false),
@@ -1149,6 +1149,8 @@ the specific language governing permissions and limitations under the Apache Lic
                 css,
                 resultsListNode;
 
+            $dropdown.show();
+
             if (this.opts.dropdownAutoWidth) {
                 resultsListNode = $('.select2-results', $dropdown)[0];
                 $dropdown.addClass('select2-drop-auto-width');