diff --git a/src/libsysprof-ui/sysprof-marks-view.c b/src/libsysprof-ui/sysprof-marks-view.c
index 93b005ad..a9dfa5da 100644
--- a/src/libsysprof-ui/sysprof-marks-view.c
+++ b/src/libsysprof-ui/sysprof-marks-view.c
@@ -30,7 +30,7 @@ typedef struct
   GtkTreeView *tree_view;
 } SysprofMarksViewPrivate;
 
-G_DEFINE_TYPE (SysprofMarksView, sysprof_marks_view, GTK_TYPE_BIN)
+G_DEFINE_TYPE_WITH_PRIVATE (SysprofMarksView, sysprof_marks_view, GTK_TYPE_BIN)
 
 static void
 sysprof_marks_view_class_init (SysprofMarksViewClass *klass)