diff --git a/src/gui/kernel/qwindow_p.h b/src/gui/kernel/qwindow_p.h
index af1233a9e2c..5103d97c6de 100644
--- a/src/gui/kernel/qwindow_p.h
+++ b/src/gui/kernel/qwindow_p.h
@@ -181,6 +181,10 @@ public:
     bool receivedExpose;
     PositionPolicy positionPolicy;
     bool positionAutomatic;
+    // resizeAutomatic suppresses resizing by QPlatformWindow::initialGeometry().
+    // It also indicates that width/height=0 is acceptable (for example, for
+    // the QRollEffect widget) and is thus not cleared in setGeometry().
+    // An alternative approach might be using -1,-1 as a default size.
     bool resizeAutomatic;
     Qt::ScreenOrientation contentOrientation;
     qreal opacity;