diff --git a/src/wp-includes/nav-menu-template.php b/src/wp-includes/nav-menu-template.php
index 3c517d150f..737d6e6c2f 100644
--- a/src/wp-includes/nav-menu-template.php
+++ b/src/wp-includes/nav-menu-template.php
@@ -397,6 +397,11 @@ function _wp_menu_item_classes_by_context( &$menu_items ) {
 		// if the menu item corresponds to the currently-requested URL
 		} elseif ( 'custom' == $menu_item->object && isset( $_SERVER['HTTP_HOST'] ) ) {
 			$_root_relative_current = untrailingslashit( $_SERVER['REQUEST_URI'] );
+
+			//if it is the customize page then it will strips the query var off the url before entering the comparison block.
+			if ( is_customize_preview() ) {
+				$_root_relative_current = strtok( untrailingslashit( $_SERVER['REQUEST_URI'] ), '?' );
+			}
 			$current_url = set_url_scheme( 'http://' . $_SERVER['HTTP_HOST'] . $_root_relative_current );
 			$raw_item_url = strpos( $menu_item->url, '#' ) ? substr( $menu_item->url, 0, strpos( $menu_item->url, '#' ) ) : $menu_item->url;
 			$item_url = set_url_scheme( untrailingslashit( $raw_item_url ) );