Index: wp-includes/nav-menu-template.php
===================================================================
--- wp-includes/nav-menu-template.php	(revision 32302)
+++ wp-includes/nav-menu-template.php	(working copy)
@@ -545,10 +545,12 @@
 
 		// if the menu item corresponds to the currently-requested URL
 		} elseif ( 'custom' == $menu_item->object ) {
-			$_root_relative_current = untrailingslashit( $_SERVER['REQUEST_URI'] );
+
+			// Use strtok() to omit any URL parameters when comparing
+			$_root_relative_current = untrailingslashit( strtok( $_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 = untrailingslashit( $raw_item_url );
+			$item_url = set_url_scheme( untrailingslashit( strtok( $raw_item_url, '?' ) ) );
 			$_indexless_current = untrailingslashit( preg_replace( '/' . preg_quote( $wp_rewrite->index, '/' ) . '$/', '', $current_url ) );
 
 			if ( $raw_item_url && in_array( $item_url, array( $current_url, $_indexless_current, $_root_relative_current ) ) ) {