Index: /CKEditor/trunk/_source/plugins/listblock/plugin.js
===================================================================
--- /CKEditor/trunk/_source/plugins/listblock/plugin.js	(revision 7201)
+++ /CKEditor/trunk/_source/plugins/listblock/plugin.js	(revision 7202)
@@ -197,6 +197,4 @@
 
 						this.element.getDocument().getById( itemId + '_option' ).setAttribute( 'aria-selected', true );
-						this.element.setAttribute( 'aria-activedescendant', itemId + '_option' );
-
 						this.onMark && this.onMark( item );
 					},
Index: /CKEditor/trunk/_source/plugins/panel/plugin.js
===================================================================
--- /CKEditor/trunk/_source/plugins/panel/plugin.js	(revision 7201)
+++ /CKEditor/trunk/_source/plugins/panel/plugin.js	(revision 7202)
@@ -246,14 +246,4 @@
 		this._.onKeyDown = block.onKeyDown && CKEDITOR.tools.bind( block.onKeyDown, block );
 
-		block.onMark = function( item )
-		{
-			holder.setAttribute( 'aria-activedescendant', item.getId() + '_option' );
-		};
-
-		block.onUnmark = function()
-		{
-			holder.removeAttribute( 'aria-activedescendant' );
-		};
-
 		block.show();