Widgets: Only scroll to the newly clicked-and-added widget if it is out of the viewport.

props shaunandrews.
see #25821.

Built from https://develop.svn.wordpress.org/trunk@26695


git-svn-id: http://core.svn.wordpress.org/trunk@26585 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/js/widgets.js

@@ -440,9 +440,24 @@ wpWidgets = {
 		// No longer "new" widget
 		widget.find( 'input.add_new' ).val('');
 
-		$( 'html, body' ).animate({
-			scrollTop: sidebar.offset().top - 130
-		}, 200 );
+		/* 
+		 * Check if any part of the sidebar is visible in the viewport. If it is, don't scroll.
+		 * Otherwise, scroll up to so the sidebar is in view.
+		 *
+		 * We do this by comparing the top and bottom, of the sidebar so see if they are within
+		 * the bounds of the viewport.
+		 */
+		var viewport_top = $(window).scrollTop(),
+			viewport_bottom = viewport_top + $(window).height(),
+			sidebar_bounds = sidebar.offset();
+		
+		sidebar_bounds.bottom = sidebar_bounds.top + sidebar.outerHeight();
+
+		if ( viewport_top > sidebar_bounds.bottom || viewport_bottom < sidebar_bounds.top ) {
+			$( 'html, body' ).animate({
+				scrollTop: sidebar.offset().top - 130
+			}, 200 );
+		}
 
 		window.setTimeout( function() {
 			// Cannot use a callback in the animation above as it fires twice,