Test default spinner template Login as administrator Go to Site administration > Development > Template library Search for "core/loading" Confirm that the spinner is correctly displayed and the effect is not wobbling. Test course modchooser Login as administrator Go to any course and press "Add an activity or resource" button in a course section. Confirm that the spinner is correctly displayed and the effect is not wobbling. Test report builder Login as administrator Go to Reports under User profile. Create a new report using "Users" as the source, and default settings. Confirm that changing between the tabs displays the spinner correctly without wobbling. In the Editor tab press the Preview button. Confirm that the spinner is correctly displayed inside the button and the effect is not wobbling. Press Filters button and then press Apply button. Confirm that the spinner is correctly displayed and the effect is not wobbling. Note: To slow some interactions down, you can add following lines to the config.php file: // Add extra timer to simulate slow JS requests. if (defined( 'AJAX_SCRIPT' )) { sleep(5); }