Index: wp-admin/includes/meta-boxes.php
===================================================================
--- wp-admin/includes/meta-boxes.php	(revision 22355)
+++ wp-admin/includes/meta-boxes.php	(working copy)
@@ -786,7 +786,7 @@
 		<p id="link-category-add" class="wp-hidden-child">
 			<label class="screen-reader-text" for="newcat"><?php _e( '+ Add New Category' ); ?></label>
 			<input type="text" name="newcat" id="newcat" class="form-required form-input-tip" value="<?php esc_attr_e( 'New category name' ); ?>" aria-required="true" />
-			<input type="button" id="link-category-add-submit" class="add:categorychecklist:linkcategorydiv button" value="<?php esc_attr_e( 'Add' ); ?>" />
+			<input type="button" id="link-category-add-submit" class="add:categorychecklist:link-category-add button" value="<?php esc_attr_e( 'Add' ); ?>" />
 			<?php wp_nonce_field( 'add-link-category', '_ajax_nonce', false ); ?>
 			<span id="category-ajax-response"></span>
 		</p>