diff --git a/src/applications/settings/panel/PhabricatorSettingsPanelDisplayPreferences.php b/src/applications/settings/panel/PhabricatorSettingsPanelDisplayPreferences.php
index a464227b8..70dd72f6a 100644
--- a/src/applications/settings/panel/PhabricatorSettingsPanelDisplayPreferences.php
+++ b/src/applications/settings/panel/PhabricatorSettingsPanelDisplayPreferences.php
@@ -1,178 +1,178 @@
 <?php
 
 final class PhabricatorSettingsPanelDisplayPreferences
   extends PhabricatorSettingsPanel {
 
   public function getPanelKey() {
     return 'display';
   }
 
   public function getPanelName() {
     return pht('Display Preferences');
   }
 
   public function getPanelGroup() {
     return pht('Application Settings');
   }
 
   public function processRequest(AphrontRequest $request) {
     $user = $request->getUser();
     $preferences = $user->loadPreferences();
 
     $pref_monospaced   = PhabricatorUserPreferences::PREFERENCE_MONOSPACED;
     $pref_editor       = PhabricatorUserPreferences::PREFERENCE_EDITOR;
     $pref_multiedit    = PhabricatorUserPreferences::PREFERENCE_MULTIEDIT;
     $pref_titles       = PhabricatorUserPreferences::PREFERENCE_TITLES;
     $pref_monospaced_textareas =
       PhabricatorUserPreferences::PREFERENCE_MONOSPACED_TEXTAREAS;
 
     $errors = array();
     $e_editor = null;
     if ($request->isFormPost()) {
       $monospaced = $request->getStr($pref_monospaced);
 
       // Prevent the user from doing stupid things.
-      $monospaced = preg_replace('/[^a-z0-9 ,"]+/i', '', $monospaced);
+      $monospaced = preg_replace('/[^a-z0-9 ,".]+/i', '', $monospaced);
 
       $preferences->setPreference($pref_titles, $request->getStr($pref_titles));
       $preferences->setPreference($pref_editor, $request->getStr($pref_editor));
       $preferences->setPreference(
         $pref_multiedit,
         $request->getStr($pref_multiedit));
       $preferences->setPreference($pref_monospaced, $monospaced);
       $preferences->setPreference(
         $pref_monospaced_textareas,
         $request->getStr($pref_monospaced_textareas));
 
       $editor_pattern = $preferences->getPreference($pref_editor);
       if (strlen($editor_pattern)) {
         $ok = PhabricatorHelpEditorProtocolController::hasAllowedProtocol(
           $editor_pattern);
         if (!$ok) {
           $allowed_key = 'uri.allowed-editor-protocols';
           $allowed_protocols = PhabricatorEnv::getEnvConfig($allowed_key);
 
           $proto_names = array();
           foreach (array_keys($allowed_protocols) as $protocol) {
             $proto_names[] = $protocol.'://';
           }
 
           $errors[] = pht(
             'Editor link has an invalid or missing protocol. You must '.
             'use a whitelisted editor protocol from this list: %s. To '.
             'add protocols, update %s.',
             implode(', ', $proto_names),
             phutil_tag('tt', array(), $allowed_key));
 
           $e_editor = pht('Invalid');
         }
       }
 
       if (!$errors) {
         $preferences->save();
         return id(new AphrontRedirectResponse())
           ->setURI($this->getPanelURI('?saved=true'));
       }
     }
 
     $example_string = <<<EXAMPLE
 // This is what your monospaced font currently looks like.
 function helloWorld() {
   alert("Hello world!");
 }
 EXAMPLE;
 
     $editor_doc_link = phutil_tag(
       'a',
       array(
         'href' => PhabricatorEnv::getDoclink(
           'User Guide: Configuring an External Editor'),
       ),
       pht('User Guide: Configuring an External Editor'));
 
     $font_default = PhabricatorEnv::getEnvConfig('style.monospace');
 
     $pref_monospaced_textareas_value = $preferences
       ->getPreference($pref_monospaced_textareas);
     if (!$pref_monospaced_textareas_value) {
       $pref_monospaced_textareas_value = 'disabled';
     }
 
     $editor_instructions = pht('Link to edit files in external editor. '.
       '%%f is replaced by filename, %%l by line number, %%r by repository '.
       'callsign, %%%% by literal %%. For documentation, see: %s',
       $editor_doc_link);
 
     $form = id(new AphrontFormView())
       ->setUser($user)
       ->appendChild(
         id(new AphrontFormSelectControl())
           ->setLabel(pht('Page Titles'))
           ->setName($pref_titles)
           ->setValue($preferences->getPreference($pref_titles))
           ->setOptions(
             array(
               'glyph' =>
               pht("In page titles, show Tool names as unicode glyphs: ".
                 "\xE2\x9A\x99"),
               'text' =>
               pht('In page titles, show Tool names as plain text: '.
                 '[Differential]'),
             )))
       ->appendChild(
         id(new AphrontFormTextControl())
         ->setLabel(pht('Editor Link'))
         ->setName($pref_editor)
         ->setCaption($editor_instructions)
         ->setError($e_editor)
         ->setValue($preferences->getPreference($pref_editor)))
       ->appendChild(
         id(new AphrontFormSelectControl())
         ->setLabel(pht('Edit Multiple Files'))
         ->setName($pref_multiedit)
         ->setOptions(array(
           '' => pht('Supported (paths separated by spaces)'),
           'disable' => pht('Not Supported'),
         ))
         ->setValue($preferences->getPreference($pref_multiedit)))
       ->appendChild(
         id(new AphrontFormTextControl())
         ->setLabel(pht('Monospaced Font'))
         ->setName($pref_monospaced)
         // Check plz
         ->setCaption(hsprintf(
           '%s<br />(%s: %s)',
           pht('Overrides default fonts in tools like Differential.'),
           pht('Default'),
           $font_default))
         ->setValue($preferences->getPreference($pref_monospaced)))
       ->appendChild(
         id(new AphrontFormMarkupControl())
         ->setValue(phutil_tag(
           'pre',
           array('class' => 'PhabricatorMonospaced'),
           $example_string)))
       ->appendChild(
         id(new AphrontFormRadioButtonControl())
         ->setLabel(pht('Monospaced Textareas'))
         ->setName($pref_monospaced_textareas)
         ->setValue($pref_monospaced_textareas_value)
         ->addButton('enabled', pht('Enabled'),
           pht('Show all textareas using the monospaced font defined above.'))
         ->addButton('disabled', pht('Disabled'), null));
 
     $form->appendChild(
       id(new AphrontFormSubmitControl())
         ->setValue(pht('Save Preferences')));
 
     $form_box = id(new PHUIObjectBoxView())
       ->setHeaderText(pht('Display Preferences'))
       ->setFormErrors($errors)
       ->setFormSaved($request->getStr('saved') === 'true')
       ->setForm($form);
 
     return array(
       $form_box,
     );
   }
 }