diff --git a/context_ui/context_ui.css b/context_ui/context_ui.css
index 4c2231e..4988074 100644
--- a/context_ui/context_ui.css
+++ b/context_ui/context_ui.css
@@ -168,6 +168,5 @@ table.context-admin input.form-text { width:90%; }
   .context-plugins .context-plugin-forms .active-form { display:block; }
 
   .context-plugins .context-plugin-form .form-checkboxes {
-    max-height:300px;
     overflow:auto;
-    }
+}
diff --git a/plugins/context_reaction_block.inc b/plugins/context_reaction_block.inc
index 52f9fe9..af7075c 100644
--- a/plugins/context_reaction_block.inc
+++ b/plugins/context_reaction_block.inc
@@ -42,13 +42,19 @@ class context_reaction_block extends context_reaction {
       $group = isset($block->context_group) ? $block->context_group : $block->module;
       if (!isset($form['selector'][$group])) {
         $form['selector'][$group] = array(
-          '#type' => 'checkboxes',
+          '#type' => 'fieldset',
+          '#collapsible' => TRUE, 
+          '#collapsed' => TRUE,
           '#title' => isset($block->context_group) ? $block->context_group : $modules[$block->module],
+        );
+        $form['selector'][$group]['checkboxes'] = array(
+          '#type' => 'checkboxes',
           '#options' => array(),
         );
       }
-      $form['selector'][$group]['#options'][$block->bid] = check_plain($block->info);
+      $form['selector'][$group]['checkboxes']['#options'][$block->bid] = check_plain($block->info);
     }
+
     ksort($form['selector']);
 
     /**