Ensure focus event is unbound after widget is destroyed

select2.js

@@ -2132,7 +2132,7 @@ the specific language governing permissions and limitations under the Apache Lic
             this.focusser.attr("id", "s2id_autogen"+idSuffix);
 
             elementLabel = $("label[for='" + this.opts.element.attr("id") + "']");
-            this.opts.element.focus(this.bind(function () { this.focus(); }));
+            this.opts.element.on('focus.select2', this.bind(function () { this.focus(); }));
 
             this.focusser.prev()
                 .text(elementLabel.text())
@@ -2727,7 +2727,7 @@ the specific language governing permissions and limitations under the Apache Lic
             this.search.prev()
                 .text($("label[for='" + this.opts.element.attr("id") + "']").text())
                 .attr('for', this.search.attr('id'));
-            this.opts.element.focus(this.bind(function () { this.focus(); }));
+            this.opts.element.on('focus.select2', this.bind(function () { this.focus(); }));
 
             this.search.on("input paste", this.bind(function() {
                 if (this.search.attr('placeholder') && this.search.val().length == 0) return;