diff --git a/src/app/puzzle/vpuzzlegraphicslayout.h b/src/app/puzzle/vpuzzlegraphicslayout.h
index 477fcfc75..a8c2c509e 100644
--- a/src/app/puzzle/vpuzzlegraphicslayout.h
+++ b/src/app/puzzle/vpuzzlegraphicslayout.h
@@ -37,7 +37,7 @@
 class VPuzzleGraphicsLayout : public QGraphicsItem
 {
 public:
-    VPuzzleGraphicsLayout(VPuzzleLayout *layout, QGraphicsItem *parent = nullptr);
+    explicit VPuzzleGraphicsLayout(VPuzzleLayout *layout, QGraphicsItem *parent = nullptr);
     ~VPuzzleGraphicsLayout();
 
     QRectF boundingRect() const override;