[devhelp] Preferences: destroy with parent

[Sébastien Wilmet <swilmet src gnome org>]

commit 2bd5f8c03d734eb6a2b5060d9dea838ac066f939
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Thu Dec 28 21:42:54 2017 +0100

    Preferences: destroy with parent
    
    Not very important, just to not leak GObjects when the app.quit GAction
    is activated.

 src/dh-preferences.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/src/dh-preferences.c b/src/dh-preferences.c
index 39bbf56..0568c50 100644
--- a/src/dh-preferences.c
+++ b/src/dh-preferences.c
@@ -666,6 +666,7 @@ dh_preferences_show_dialog (GtkWindow *parent)
         if (parent != gtk_window_get_transient_for (GTK_WINDOW (prefs_dialog))) {
                 gtk_window_set_transient_for (GTK_WINDOW (prefs_dialog),
                                               parent);
+                gtk_window_set_destroy_with_parent (GTK_WINDOW (prefs_dialog), TRUE);
         }
 
         gtk_window_present (GTK_WINDOW (prefs_dialog));