Index: inc/io/main_connection.hpp
===================================================================
--- inc/io/main_connection.hpp (revision d52024b61c539e5ef815056fa0270adb3f7693c4)
+++ inc/io/main_connection.hpp (revision 196195f98691fec8582ba12dd873fedc2d55b35f)
@@ -23,4 +23,7 @@
 #include <glibmm/refptr.h>
 #include <glibmm/iochannel.h>
+#ifdef WIN32
+# include <gtkmm/window.h>
+#endif
 #include <net6/non_copyable.hpp>
 #include <net6/socket.hpp>