Can't manage display for article I have done something and can no longer edit the manage display pages for the article content type .  When I try to visit them I fall out of the usual rich html interface into a page whose code is attached below.  I think that this is happening because I have accidentally damaged or removed the full content view mode for the article, but I am a newbie so I am really not sure.  I was playing with Display Suite when this problem began.

Any ideas what is going on? and how to fix it?  Thanks.  

  &lt;div id="branding" class="clearfix"&gt;
    &lt;h2 class="element-invisible"&gt;You are here&lt;/h2&gt;&lt;div class="breadcrumb"&gt;&lt;a href="/drupal7/"&gt;Home&lt;/a&gt; » &lt;a href="/drupal7/?q=admin"&gt;Administration&lt;/a&gt; » &lt;a href="/drupal7/?q=admin/structure" title="Administer blocks, content types, menus, etc."&gt;Structure&lt;/a&gt; » &lt;a href="/drupal7/?q=admin/structure/types" title="Manage content types, including default status, front page promotion, comment settings, etc."&gt;Content types&lt;/a&gt; » &lt;a href="/drupal7/?q=admin/structure/types/manage/article"&gt;Article&lt;/a&gt;&lt;/div&gt;              &lt;h1 class="page-title"&gt;Article&lt;/h1&gt;
        &lt;div class="add-or-remove-shortcuts add-shortcut"&gt;&lt;a href="/drupal7/?q=admin/config/user-interface/shortcut/shortcut-set-1/add-link-inline&amp;amp;link=admin/structure/types/manage/article/display&amp;amp;name=Article&amp;amp;destination=admin/structure/types/manage/article/display&amp;amp;token=sfNEjW3fhzg0KSwbxJKEEx_mwmWcqqCQjgxWGn5Q27A"&gt;&lt;span class="icon"&gt;&lt;/span&gt;&lt;span class="text"&gt;Add to &lt;em class="placeholder"&gt;Default&lt;/em&gt; shortcuts&lt;/span&gt;&lt;/a&gt;&lt;/div&gt;    &lt;h2 class="element-invisible"&gt;Primary tabs&lt;/h2&gt;&lt;ul class="tabs primary"&gt;&lt;li&gt;&lt;a href="/drupal7/?q=admin/structure/types/manage/article"&gt;Edit&lt;/a&gt;&lt;/li&gt;
&lt;li&gt;&lt;a href="/drupal7/?q=admin/structure/types/manage/article/fields"&gt;Manage fields&lt;/a&gt;&lt;/li&gt;
&lt;li class="active"&gt;&lt;a href="/drupal7/?q=admin/structure/types/manage/article/display" class="active"&gt;Manage display&lt;span class="element-invisible"&gt;(active tab)&lt;/span&gt;&lt;/a&gt;&lt;/li&gt;
&lt;li&gt;&lt;a href="/drupal7/?q=admin/structure/types/manage/article/comment/fields"&gt;Comment fields&lt;/a&gt;&lt;/li&gt;
&lt;li&gt;&lt;a href="/drupal7/?q=admin/structure/types/manage/article/comment/display"&gt;Comment display&lt;/a&gt;&lt;/li&gt;
&lt;/ul&gt;  &lt;/div&gt;

  &lt;div id="page"&gt;
          &lt;div class="tabs-secondary clearfix"&gt;&lt;ul class="tabs secondary"&gt;&lt;h2 class="element-invisible"&gt;Secondary tabs&lt;/h2&gt;&lt;ul class="tabs secondary"&gt;&lt;li class="active"&gt;&lt;a href="/drupal7/?q=admin/structure/types/manage/article/display" class="active"&gt;Default&lt;span class="element-invisible"&gt;(active tab)&lt;/span&gt;&lt;/a&gt;&lt;/li&gt;
&lt;li&gt;&lt;a href="/drupal7/?q=admin/structure/types/manage/article/display/teaser"&gt;Teaser&lt;/a&gt;&lt;/li&gt;
&lt;/ul&gt;&lt;/ul&gt;&lt;/div&gt;

    &lt;div id="content" class="clearfix"&gt;
      &lt;div class="element-invisible"&gt;&lt;a id="main-content"&gt;&lt;/a&gt;&lt;/div&gt;
                    &lt;div id="help"&gt;
            &lt;div class="region region-help"&gt;
    &lt;div id="block-system-help" class="block block-system"&gt;


  &lt;div class="content"&gt;
    &lt;p&gt;Content items can be displayed using different view modes: Teaser, Full content, Print, RSS, etc. &lt;em&gt;Teaser&lt;/em&gt; is a short format that is typically used in lists of multiple content items. &lt;em&gt;Full content&lt;/em&gt; is typically used when the content is displayed on its own page.&lt;/p&gt;&lt;p&gt;Here, you can define which fields are shown and hidden when &lt;em class="placeholder"&gt;Article&lt;/em&gt; content is displayed in each view mode, and define how the fields are displayed in each view mode.&lt;/p&gt;
  &lt;/div&gt;
&lt;/div&gt;
  &lt;/div&gt;
        &lt;/div&gt;
Did you enable text format as Full Html.

In your html code there were two closing div are missed. here is the closing div added.

&lt;div class="clearfix" id="branding"&gt;
    &lt;h2 class="element-invisible"&gt;You are here&lt;/h2&gt;

    &lt;div class="breadcrumb"&gt;&lt;a href="/drupal7/"&gt;Home&lt;/a&gt; » &lt;a href="/drupal7/?q=admin"&gt;Administration&lt;/a&gt; » &lt;a href="/drupal7/?q=admin/structure" title="Administer blocks, content types, menus, etc."&gt;Structure&lt;/a&gt; » &lt;a href="/drupal7/?q=admin/structure/types" title="Manage content types, including default status, front page promotion, comment settings, etc."&gt;Content types&lt;/a&gt; » &lt;a href="/drupal7/?q=admin/structure/types/manage/article"&gt;Article&lt;/a&gt;&lt;/div&gt;

    &lt;h1 class="page-title"&gt;Article&lt;/h1&gt;

    &lt;div class="add-or-remove-shortcuts add-shortcut"&gt;&lt;a href="/drupal7/?q=admin/config/user-interface/shortcut/shortcut-set-1/add-link-inline&amp;amp;link=admin/structure/types/manage/article/display&amp;amp;name=Article&amp;amp;destination=admin/structure/types/manage/article/display&amp;amp;token=sfNEjW3fhzg0KSwbxJKEEx_mwmWcqqCQjgxWGn5Q27A"&gt;&lt;span class="text"&gt;Add to &lt;em class="placeholder"&gt;Default&lt;/em&gt; shortcuts&lt;/span&gt;&lt;/a&gt;&lt;/div&gt;

    &lt;h2 class="element-invisible"&gt;Primary tabs&lt;/h2&gt;

    &lt;ul class="tabs primary"&gt;
        &lt;li&gt;&lt;a href="/drupal7/?q=admin/structure/types/manage/article"&gt;Edit&lt;/a&gt;&lt;/li&gt;
        &lt;li&gt;&lt;a href="/drupal7/?q=admin/structure/types/manage/article/fields"&gt;Manage fields&lt;/a&gt;&lt;/li&gt;
        &lt;li class="active"&gt;&lt;a class="active" href="/drupal7/?q=admin/structure/types/manage/article/display"&gt;Manage display&lt;span class="element-invisible"&gt;(active tab)&lt;/span&gt;&lt;/a&gt;&lt;/li&gt;
        &lt;li&gt;&lt;a href="/drupal7/?q=admin/structure/types/manage/article/comment/fields"&gt;Comment fields&lt;/a&gt;&lt;/li&gt;
        &lt;li&gt;&lt;a href="/drupal7/?q=admin/structure/types/manage/article/comment/display"&gt;Comment display&lt;/a&gt;&lt;/li&gt;
    &lt;/ul&gt;
&lt;/div&gt;

&lt;div id="page"&gt;
    &lt;div class="tabs-secondary clearfix"&gt;
        &lt;h2 class="element-invisible"&gt;Secondary tabs&lt;/h2&gt;

        &lt;ul class="tabs secondary"&gt;
            &lt;li&gt;
                &lt;ul class="tabs secondary"&gt;
                    &lt;li class="active"&gt;&lt;a class="active" href="/drupal7/?q=admin/structure/types/manage/article/display"&gt;Default&lt;span class="element-invisible"&gt;(active tab)&lt;/span&gt;&lt;/a&gt;&lt;/li&gt;
                    &lt;li&gt;&lt;a href="/drupal7/?q=admin/structure/types/manage/article/display/teaser"&gt;Teaser&lt;/a&gt;&lt;/li&gt;
                &lt;/ul&gt;
            &lt;/li&gt;
        &lt;/ul&gt;
    &lt;/div&gt;

    &lt;div class="clearfix" id="content"&gt;
        &lt;div class="element-invisible"&gt;&amp;nbsp;&lt;/div&gt;

        &lt;div id="help"&gt;
            &lt;div class="region region-help"&gt;
                &lt;div class="block block-system" id="block-system-help"&gt;
                    &lt;div class="content"&gt;
                        &lt;p&gt;Content items can be displayed using different view modes: Teaser, Full content, Print, RSS, etc. &lt;em&gt;Teaser&lt;/em&gt; is a short format that is typically used in lists of multiple content items. &lt;em&gt;Full content&lt;/em&gt; is typically used when the content is displayed on its own page.&lt;/p&gt;

                        &lt;p&gt;Here, you can define which fields are shown and hidden when &lt;em class="placeholder"&gt;Article&lt;/em&gt; content is displayed in each view mode, and define how the fields are displayed in each view mode.&lt;/p&gt;
                    &lt;/div&gt;
                &lt;/div&gt;
            &lt;/div&gt;
        &lt;/div&gt;
    &lt;/div&gt;
&lt;/div&gt;