Media: avoid page scrolling when opening the media modal.

Moves focus to a proper element within the media modal to avoid the underlying
page to scroll to the bottom. Removes the media modal `freeze` option.

Props andreiglingeanu, adamsilverstein.
Merges [42624] to the 4.9 branch.
Fixes #39859.
Built from https://develop.svn.wordpress.org/branches/4.9@42627


git-svn-id: http://core.svn.wordpress.org/branches/4.9@42456 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/js/media-views.js

@@ -4173,10 +4173,6 @@ Modal = wp.media.View.extend(/** @lends wp.media.view.Modal.prototype */{
 	tagName:  'div',
 	template: wp.template('media-modal'),
 
-	attributes: {
-		tabindex: 0
-	},
-
 	events: {
 		'click .media-modal-backdrop, .media-modal-close': 'escapeHandler',
 		'keydown': 'keydown'
@@ -4188,8 +4184,7 @@ Modal = wp.media.View.extend(/** @lends wp.media.view.Modal.prototype */{
 		_.defaults( this.options, {
 			container: document.body,
 			title:     '',
-			propagate: true,
+			propagate: true
-			freeze:    true
 		});
 
 		this.focusManager = new wp.media.view.FocusManager({
@@ -4244,7 +4239,6 @@ Modal = wp.media.View.extend(/** @lends wp.media.view.Modal.prototype */{
 	 */
 	open: function() {
 		var $el = this.$el,
-			options = this.options,
 			mceEditor;
 
 		if ( $el.is(':visible') ) {
@@ -4257,13 +4251,6 @@ Modal = wp.media.View.extend(/** @lends wp.media.view.Modal.prototype */{
 			this.attach();
 		}
 
-		// If the `freeze` option is set, record the window's scroll position.
-		if ( options.freeze ) {
-			this._freeze = {
-				scrollTop: $( window ).scrollTop()
-			};
-		}
-
 		// Disable page scrolling.
 		$( 'body' ).addClass( 'modal-open' );
 
@@ -4271,7 +4258,7 @@ Modal = wp.media.View.extend(/** @lends wp.media.view.Modal.prototype */{
 
 		// Try to close the onscreen keyboard
 		if ( 'ontouchend' in document ) {
-			if ( ( mceEditor = window.tinymce && window.tinymce.activeEditor )  && ! mceEditor.isHidden() && mceEditor.iframeElement ) {
+			if ( ( mceEditor = window.tinymce && window.tinymce.activeEditor ) && ! mceEditor.isHidden() && mceEditor.iframeElement ) {
 				mceEditor.iframeElement.focus();
 				mceEditor.iframeElement.blur();
 
@@ -4281,7 +4268,8 @@ Modal = wp.media.View.extend(/** @lends wp.media.view.Modal.prototype */{
 			}
 		}
 
-		this.$el.focus();
+		// Set initial focus on the content instead of this view element, to avoid page scrolling.
+		this.$( '.media-modal' ).focus();
 
 		return this.propagate('open');
 	},
@@ -4291,8 +4279,6 @@ Modal = wp.media.View.extend(/** @lends wp.media.view.Modal.prototype */{
 	 * @returns {wp.media.view.Modal} Returns itself to allow chaining
 	 */
 	close: function( options ) {
-		var freeze = this._freeze;
-
 		if ( ! this.views.attached || ! this.$el.is(':visible') ) {
 			return this;
 		}
@@ -4312,11 +4298,6 @@ Modal = wp.media.View.extend(/** @lends wp.media.view.Modal.prototype */{
 
 		this.propagate('close');
 
-		// If the `freeze` option is set, restore the container's scroll position.
-		if ( freeze ) {
-			$( window ).scrollTop( freeze.scrollTop );
-		}
-
 		if ( options && options.escape ) {
 			this.propagate('escape');
 		}

wp-includes/media-template.php

@@ -162,7 +162,7 @@ function wp_print_media_templates() {
 	</script>
 
 	<script type="text/html" id="tmpl-media-modal">
-		<div class="<?php echo $class; ?>">
+		<div tabindex="0" class="<?php echo $class; ?>">
 			<button type="button" class="media-modal-close"><span class="media-modal-icon"><span class="screen-reader-text"><?php _e( 'Close media panel' ); ?></span></span></button>
 			<div class="media-modal-content"></div>
 		</div>

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9.3-beta1-42626';
+$wp_version = '4.9.3-beta1-42627';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.