[pan2] Fix for bug #697983 size of preference window to large

[Petr Kovář <pmkovar src gnome org>]

commit ee7e4add92459a6162c19e5a5770776d1b8fbff9
Author: Detlef Graef <detlef graef yahoo de>
Date:   Tue Mar 14 20:17:26 2017 +0100

    Fix for bug #697983 size of preference window to large

 pan/gui/gui.cc |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/pan/gui/gui.cc b/pan/gui/gui.cc
index 2e4069c..3956f53 100644
--- a/pan/gui/gui.cc
+++ b/pan/gui/gui.cc
@@ -952,6 +952,7 @@ void GUI :: do_show_preferences_dialog ()
 {
   PrefsDialog * dialog = new PrefsDialog (_prefs, get_window(_root));
   g_signal_connect (dialog->root(), "destroy", G_CALLBACK(prefs_dialog_destroyed_cb), this);
+  gtk_widget_set_size_request(dialog->root(), 800, 600);
   gtk_widget_show (dialog->root());
 }
 void GUI :: do_show_group_preferences_dialog ()