diff --git a/phpdotnet/phd/Package/PHP/Web.php b/phpdotnet/phd/Package/PHP/Web.php
index ad36b7cf..0489113c 100644
--- a/phpdotnet/phd/Package/PHP/Web.php
+++ b/phpdotnet/phd/Package/PHP/Web.php
@@ -204,7 +204,14 @@ public function header($id) {
             "alternatives" => $this->cchunk["alternatives"],
             "source" => $this->sourceInfo($id),
         );
-        $setup["history"] = $this->history[$setup["source"]["path"]] ?? [];
+        $history = $this->history ?? [];
+
+        $sourcePath = $setup["source"]["path"] ?? null;
+
+        $setup["history"] = $sourcePath !== null
+            ? ($history[$sourcePath] ?? [])
+            : [];
+
         if ($this->getChildren($id)) {
             $lang = $this->config->language;
             $setup["extra_header_links"] = array(