[gtk/mcatanzaro/unparent-warning] listbox: unparent new header only if it has a parent

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 10ec545ecb5c3c727620999844b379bbe4d53623
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Thu Jan 7 10:26:03 2021 -0600

    listbox: unparent new header only if it has a parent
    
    It's no longer OK to unparent a widget that has no parent.

 gtk/gtklistbox.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/gtk/gtklistbox.c b/gtk/gtklistbox.c
index 72bc7c8539..a960793707 100644
--- a/gtk/gtklistbox.c
+++ b/gtk/gtklistbox.c
@@ -2232,7 +2232,8 @@ gtk_list_box_update_header (GtkListBox    *box,
           if (new_header != NULL)
             {
               g_hash_table_insert (box->header_hash, new_header, row);
-              gtk_widget_unparent (new_header);
+              if (gtk_widget_get_parent (new_header) != NULL)
+                gtk_widget_unparent (new_header);
               gtk_widget_set_parent (new_header, GTK_WIDGET (box));
               gtk_widget_show (new_header);
             }