diff --git a/src/gui/painting/qbrush.h b/src/gui/painting/qbrush.h
index 4d8c97e255e..e09ad3e1af0 100644
--- a/src/gui/painting/qbrush.h
+++ b/src/gui/painting/qbrush.h
@@ -243,7 +243,7 @@ private:
             qreal cx, cy, angle;
         } conical;
     } m_data;
-    void *dummy;
+    void *dummy; // ### Qt 6: replace with actual content (CoordinateMode, InterpolationMode, ...)
 };
 
 inline void QGradient::setSpread(Spread aspread)