core/modules/system/system.admin.css  |   30 ++++++++++++++++++++++++++++--
 core/modules/system/system.admin.inc  |   12 +++++-------
 core/modules/system/system.base.css   |    1 +
 core/modules/system/system.modules.js |   18 ++++++++++++------
 4 files changed, 46 insertions(+), 15 deletions(-)

diff --git a/core/modules/system/system.admin.css b/core/modules/system/system.admin.css
index 5716d03..abeb5ce 100644
--- a/core/modules/system/system.admin.css
+++ b/core/modules/system/system.admin.css
@@ -61,6 +61,9 @@ small .admin-link:after {
 #system-modules div.incompatible {
   font-weight: bold;
 }
+#system-modules th.priority-medium {
+  width: 100%;
+}
 #system-modules td {
   vertical-align: top;
 }
@@ -81,11 +84,34 @@ small .admin-link:after {
   color: #5c5c5b;
   height: 20px;
   line-height: 20px;
+  position: relative;
+}
+#system-modules .description .inner .details {
   overflow: hidden; /* truncates descriptions if too long */
+  position: absolute;
+  white-space: nowrap;
+  width: 100%;
+  text-overflow: ellipsis;
+}
+#system-modules .expanded .description .inner {
+  position: static;
+  height: auto;
 }
+#system-modules .expanded .description .inner .details {
+  overflow: auto;
+  position: static;
+  white-space: normal;
+  width: auto;
+}
+#system-modules .expanded .description .inner .details .text {
+  -webkit-hyphens: auto;
+  -moz-hyphens: auto;
+  hyphens: auto;
+}
+
 @media screen and (max-width: 40em) {
-  #system-modules .description .inner .text {
-    visibility: hidden;
+  #system-modules .description .inner .details .text {
+    display: none;
   }
 }
 #system-modules .description .version {
diff --git a/core/modules/system/system.admin.inc b/core/modules/system/system.admin.inc
index 0f64653..78cbade 100644
--- a/core/modules/system/system.admin.inc
+++ b/core/modules/system/system.admin.inc
@@ -2514,10 +2514,11 @@ function theme_system_modules_fieldset($variables) {
 
     // Add the description, along with any modules it requires.
     $col3 = '<div class="inner">';
+    $version = '';
     if (!empty($module['version']['#markup'])) {
-      $col3 .= '<span class="version">' . drupal_render($module['version']) . ' - </span>';
+      $version = '<span class="version">' . drupal_render($module['version']) . '</span>';
     }
-    $col3 .= '<span class="text">' . drupal_render($module['description']) . '</span></div>';
+    $col3 .= '<span class="details">' . $version . '<span class="text"> — ' . drupal_render($module['description']) . '</span></span></div>';
     $col3 .= '  <div class="requirements">';
     if ($module['#requires']) {
       $col3 .= '<div class="admin-requirements">' . t('Requires: !module-list', array('!module-list' => implode(', ', $module['#requires']))) . '</div>';
@@ -2531,7 +2532,8 @@ function theme_system_modules_fieldset($variables) {
     foreach (array('help', 'permissions', 'configure') as $key) {
       $col3 .= drupal_render($module['links'][$key]);
     }
-    $row[] = $col3;
+    $col3 .= '  </div>';
+    $row[] = array('class' => array('description'), 'data' => $col3);
     $rows[] = $row;
   }
 
@@ -2748,10 +2750,6 @@ function system_date_time_formats() {
       $row[] = array('data' => l(t('delete'), 'admin/config/regional/date-time/formats/' . $format['dfid'] . '/delete'));
       $rows[] = $row;
     }
-    $col3 .= '  </div>';
-
-    $row[] = array('class' => array('description'), 'data' => $col3);
-
   }
 
   $build['date_formats_table'] = array(
diff --git a/core/modules/system/system.base.css b/core/modules/system/system.base.css
index 610d94d..6d0ca78 100644
--- a/core/modules/system/system.base.css
+++ b/core/modules/system/system.base.css
@@ -144,6 +144,7 @@ div.tree-child-horizontal {
 table.sticky-header {
   background-color: #fff;
   margin-top: 0;
+  z-index: 200;
 }
 
 /**
diff --git a/core/modules/system/system.modules.js b/core/modules/system/system.modules.js
index 117cf64..7c8c424 100644
--- a/core/modules/system/system.modules.js
+++ b/core/modules/system/system.modules.js
@@ -5,13 +5,13 @@
 $.extend(Drupal.settings, {
   hideModules: {
     method: 'slideToggle',
-    args: 'fast'
+    duration: 'fast'
   }
 });
 
- /**
-  * Show/hide the requirements information on modules page.
-  */
+/**
+ * Show/hide the requirements information on modules page.
+ */
 Drupal.behaviors.hideModuleInformation = {
   attach: function (context, settings) {
     var $table = $('#system-modules').once('expand-modules');
@@ -23,8 +23,10 @@ Drupal.behaviors.hideModuleInformation = {
         if (e.type === 'click' || (e.type === 'keydown' && e.keyCode === 13)) {
           e.preventDefault();
           var $tr = $(this);
-          $tr.toggleClass('expanded');
-          $tr.find('.requirements, .links')[effect.method](effect.args);
+          $tr.find('.requirements, .links')[effect.method](effect.duration)
+          .promise().done(function() {
+            $tr.toggleClass('expanded');
+          });
         }
       });
       // Makes the whole cell a click target.
@@ -39,6 +41,10 @@ Drupal.behaviors.hideModuleInformation = {
       $tbodies.on('click', 'input', function (e) {
         e.stopPropagation();
       });
+      // Catch the event on the checkbox to avoid triggering previous handler.
+      $tbodies.on('mousedown', 'label', function (e) {
+        e.preventDefault();
+      });
     }
     $table.find('.requirements, .links').hide();
   }