diff --git a/gtk/gtklistbase.c b/gtk/gtklistbase.c
index 8bc7271c26..0e38bd42d1 100644
--- a/gtk/gtklistbase.c
+++ b/gtk/gtklistbase.c
@@ -639,6 +639,8 @@ gtk_list_base_set_adjustment (GtkListBase    *self,
 
   if (adjustment == NULL)
     adjustment = gtk_adjustment_new (0.0, 0.0, 0.0, 0.0, 0.0, 0.0);
+  else
+    gtk_adjustment_configure (adjustment, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0);
   g_object_ref_sink (adjustment);
 
   gtk_list_base_clear_adjustment (self, orientation);
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index adc18da4f0..123bf17745 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -5972,6 +5972,9 @@ gtk_widget_reposition_after (GtkWidget *widget,
   prev_parent = priv->parent;
   prev_previous = priv->prev_sibling;
 
+  if (priv->parent == parent && previous_sibling == prev_previous)
+    return;
+
   if (priv->parent != NULL && priv->parent != parent)
     {
       g_warning ("Can't set new parent %s %p on widget %s %p, "