diff --git a/src/widgets/dialogs/qdialog.cpp b/src/widgets/dialogs/qdialog.cpp
index 16730ed2c4e..27466d03d6c 100644
--- a/src/widgets/dialogs/qdialog.cpp
+++ b/src/widgets/dialogs/qdialog.cpp
@@ -324,6 +324,10 @@ QVariant QDialogPrivate::styleHint(QPlatformDialogHelper::StyleHint hint) const
 
     \snippet dialogs/dialogs.cpp extension
 
+    By setting the \l{QLayout::}{sizeConstraint} property of the dialog's
+    layout to \l{QLayout::}{SetFixedSize}, the dialog will not be resizable
+    by the user, and will automatically shrink when the extension gets hidden.
+
     \sa QDialogButtonBox, QTabWidget, QWidget, QProgressDialog,
         {Standard Dialogs Example}
 */
diff --git a/src/widgets/doc/snippets/dialogs/dialogs.cpp b/src/widgets/doc/snippets/dialogs/dialogs.cpp
index 16b136df4b8..0990d7d7c46 100644
--- a/src/widgets/doc/snippets/dialogs/dialogs.cpp
+++ b/src/widgets/doc/snippets/dialogs/dialogs.cpp
@@ -236,6 +236,8 @@ void extension()
     QVBoxLayout *mainLayout;
 
 //! [extension]
+    mainLayout->setSizeConstraint(QLayout::SetFixedSize);
+
     findButton = new QPushButton(tr("&Find"));
     moreButton = new QPushButton(tr("&More..."));
     moreButton->setCheckable(true);