diff --git a/src/dialogs/FlagDialog.h b/src/dialogs/FlagDialog.h
index 9a9c6b83..ed187d48 100644
--- a/src/dialogs/FlagDialog.h
+++ b/src/dialogs/FlagDialog.h
@@ -2,6 +2,7 @@
 #define FLAGDIALOG_H
 
 #include <QDialog>
+#include <QIntValidator>
 #include <memory>
 #include "Cutter.h"