--- window.hh_org	2022-06-15 11:26:06.696263156 +0200
+++ window.hh	2022-06-15 11:26:18.923296588 +0200
@@ -72,6 +72,7 @@
 #include <sstream>
 #include <algorithm>
 #include <functional>
+#include <optional>
 #include <unordered_map>
 
 namespace aec = OB::Term::ANSI_Escape_Codes;