Index: includes/ajax.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/ajax.inc,v
retrieving revision 1.41
diff -u -p -r1.41 ajax.inc
--- includes/ajax.inc	23 Dec 2010 04:26:31 -0000	1.41
+++ includes/ajax.inc	25 Dec 2010 23:04:08 -0000
@@ -587,13 +587,8 @@ function ajax_pre_render_element($elemen
       case 'submit':
       case 'button':
       case 'image_button':
-        // Use the mousedown instead of the click event because form
-        // submission via pressing the enter key triggers a click event on
-        // submit inputs, inappropriately triggering AJAX behaviors.
-        $element['#ajax']['event'] = 'mousedown';
-        // Attach an additional event handler so that AJAX behaviors
-        // can be triggered still via keyboard input.
-        $element['#ajax']['keypress'] = TRUE;
+      case 'link':
+        $element['#ajax']['event'] = 'click';
         break;
 
       case 'password':
@@ -608,10 +603,6 @@ function ajax_pre_render_element($elemen
         $element['#ajax']['event'] = 'change';
         break;
 
-      case 'link':
-        $element['#ajax']['event'] = 'click';
-        break;
-
       default:
         return $element;
     }
Index: misc/ajax.js
===================================================================
RCS file: /cvs/drupal/drupal/misc/ajax.js,v
retrieving revision 1.35
diff -u -p -r1.35 ajax.js
--- misc/ajax.js	23 Dec 2010 04:26:31 -0000	1.35
+++ misc/ajax.js	25 Dec 2010 23:04:09 -0000
@@ -55,7 +55,7 @@ Drupal.behaviors.AJAX = {
 
     // This class means to submit the form to the action using AJAX.
     $('.use-ajax-submit:not(.ajax-processed)').addClass('ajax-processed').each(function () {
-      var element_settings = {};
+      var element_settings = {event: 'click'};
 
       // AJAX submits specified in this manner automatically submit to the
       // normal form action.
@@ -63,8 +63,6 @@ Drupal.behaviors.AJAX = {
       // Form submit button clicks need to tell the form what was clicked so
       // it gets passed in the POST request.
       element_settings.setClick = true;
-      // Form buttons use the 'click' event rather than mousedown.
-      element_settings.event = 'click';
       // Clicked form buttons look better with the throbber than the progress bar.
       element_settings.progress = { 'type': 'throbber' };
 
@@ -99,8 +97,8 @@ Drupal.behaviors.AJAX = {
 Drupal.ajax = function (base, element, element_settings) {
   var defaults = {
     url: 'system/ajax',
-    event: 'mousedown',
-    keypress: true,
+    event: 'click',
+    keypress: false,
     selector: '#' + base,
     effect: 'none',
     speed: 'none',
Index: modules/field_ui/field_ui.js
===================================================================
RCS file: /cvs/drupal/drupal/modules/field_ui/field_ui.js,v
retrieving revision 1.8
diff -u -p -r1.8 field_ui.js
--- modules/field_ui/field_ui.js	21 Nov 2010 08:50:49 -0000	1.8
+++ modules/field_ui/field_ui.js	25 Dec 2010 23:05:08 -0000
@@ -236,7 +236,7 @@ Drupal.fieldUIOverview = {
 
       // Fire the AJAX update.
       $('input[name=refresh_rows]').val(rowNames.join(' '));
-      $('input#edit-refresh').mousedown();
+      $('input#edit-refresh').click();
 
       // Disabled elements do not appear in POST ajax data, so we mark the
       // elements disabled only after firing the request.