session changed, css, postcode range

prijs-per-postcode.php

@@ -1,7 +1,6 @@
 <?php
 
-session_start();
-require_once "session_dialog.php";
+require_once plugin_dir_path(__FILE__) . "session_dialog.php";
 /*
  * Plugin Name: prijzen per poscode range
  * Description:  posctcodes in de 5000-5800 range krijgen een lokaal tarief aangeboden.
@@ -19,12 +18,16 @@ class PrijsPerPostcode
 {
     public function __construct()
     {
-        add_action("init", [$this, "init"]);
+        add_action("init", [$this, "init"], 1);
         add_action("rest_api_init", "register_modal_api");
     }
 
     public function init()
     {
+        if (session_status() == PHP_SESSION_NONE) {
+            ob_start();
+            @session_start();
+        }
         $uri = $_SERVER["REQUEST_URI"];
         init_postcode_handlers($uri);
         add_filter("woocommerce_sale_flash", "__return_null");