diff -r 34716fd837a4 -r be944660c56a wp/wp-admin/js/widgets/media-widgets.js
--- a/wp/wp-admin/js/widgets/media-widgets.js	Tue Dec 15 15:52:01 2020 +0100
+++ b/wp/wp-admin/js/widgets/media-widgets.js	Wed Sep 21 18:19:35 2022 +0200
@@ -551,13 +551,13 @@
 			// Update the title.
 			control.$el.on( 'input change', '.title', function updateTitle() {
 				control.model.set({
-					title: $.trim( $( this ).val() )
+					title: $( this ).val().trim()
 				});
 			});
 
 			// Update link_url attribute.
 			control.$el.on( 'input change', '.link', function updateLinkUrl() {
-				var linkUrl = $.trim( $( this ).val() ), linkType = 'custom';
+				var linkUrl = $( this ).val().trim(), linkType = 'custom';
 				if ( control.selectedAttachment.get( 'linkUrl' ) === linkUrl || control.selectedAttachment.get( 'link' ) === linkUrl ) {
 					linkType = 'post';
 				} else if ( control.selectedAttachment.get( 'url' ) === linkUrl ) {
@@ -1212,7 +1212,7 @@
 			return;
 		}
 
-		idBase = widgetForm.find( '> .widget-control-actions > .id_base' ).val();
+		idBase = widgetForm.find( '.id_base' ).val();
 
 		ControlConstructor = component.controlConstructors[ idBase ];
 		if ( ! ControlConstructor ) {
@@ -1320,9 +1320,15 @@
 			});
 
 			// Accessibility mode.
-			$( window ).on( 'load', function() {
+			if ( document.readyState === 'complete' ) {
+				// Page is fully loaded.
 				component.setupAccessibleMode();
-			});
+			} else {
+				// Page is still loading.
+				$( window ).on( 'load', function() {
+					component.setupAccessibleMode();
+				});
+			}
 		});
 	};