Remove redundant tabindex attr from buttons.

drag_and_drop_v2/public/js/drag_and_drop.js

@@ -261,7 +261,7 @@ function DragAndDropTemplates(configuration) {
             h('div.keyboard-help-dialog', [
                 h('div.modal-window-overlay'),
                 h('div.modal-window', {attributes: {role: 'dialog', 'aria-labelledby': labelledby_id, tabindex: -1}}, [
-                    h('button.modal-dismiss-button.unbutton', {attributes: {tabindex: 1}}, [
+                    h('button.modal-dismiss-button.unbutton', [
                         h('span.fa.fa-remove', {attributes: {'aria-hidden': true}}),
                         h('span.sr', gettext('Close'))
                     ]),
@@ -321,8 +321,7 @@ function DragAndDropTemplates(configuration) {
                     'button.unbutton.btn-default.btn-small',
                     {
                         className: buttonClass,
-                        disabled: options.disabled || options.spinner || false,
-                        attributes: {tabindex: 0}
+                        disabled: options.disabled || options.spinner || false
                     },
                     [
                         h("span.btn-icon.fa", {className: iconClass, attributes: {"aria-hidden": true}}),
@@ -755,7 +754,7 @@ function DragAndDropBlock(runtime, element, configuration) {
     };
 
     var focusModalButton = function() {
-        $root.find('.keyboard-help-dialog .modal-dismiss-button ').focus();
+        $root.find('.keyboard-help-dialog .modal-dismiss-button').focus();
     };
 
     var showKeyboardHelp = function(evt) {

tests/integration/test_render.py

@@ -217,7 +217,6 @@ class TestDragAndDropRender(BaseIntegrationTest):
         self.scroll_down(250)
 
         button = self._get_go_to_beginning_button()
-        self.assertEqual(button.get_attribute('tabindex'), '0')
         # Button is only visible to screen reader users by default.
         self.assertIn('sr', button.get_attribute('class').split())
         # Set focus to the element (cannot find a way to do this without execute_script).