Index: wp-includes/js/tinymce/plugins/wplink/js/wplink.dev.js
===================================================================
--- wp-includes/js/tinymce/plugins/wplink/js/wplink.dev.js	(revision 17357)
+++ wp-includes/js/tinymce/plugins/wplink/js/wplink.dev.js	(working copy)
@@ -154,6 +154,7 @@
 			// Leave the new tab setting as-is.
 			inputs.url.val('http://');
 			inputs.title.val('');
+			inputs.search.val( tinyMCEPopup.editor.selection.getContent({ format: 'text' }) ).trigger('keyup');
 		},
 
 		searchInternalLinks : function() {