jQuery UI is missing in all pages I am having the errors in console for jQuery UI. The jQuery Update module (7.x-2.4) is being used in my theme, and I have no idea why it is not including the jQuery UI. The following is the screenshot of the errors I get. In the view source I don't find jqueryui.js.



It happens in all the browsers. I also tried using the files from the jQuery CDN, but it didn't work at all. These errors are creating many troubles in the admin area. Many things aren't working: The Views interface is broken and the MD Slider is broken.
jQuery UI is not included on every request by default. Drupal only adds it when it is requested.  You can ask Drupal to include the libraries you want on some or all pages with a custom module inside a hook_init or hook_preprocess_page.  Something like this would work:

function MYMODULE_init() {
  drupal_add_library('system', 'ui');
  drupal_add_library('system', 'ui.widget');
  ...
}


For a full list of all system libraries see the API documentation here.

Also, new versions of jQuery do not play nice with many system forms (views as you noted but also rules &amp; panels can have issues).  Newer versions of the jquery_update module have the option of setting a different version of jQuery for administration pages. You will probably want to set that to 1.5 (the version D7 ships with), or add the jquery.migrate script to your theme to allow older jQuery to run on newer versions.