Add GtkWidget::window_state_event() implementation to GimpImageWindow

Keep an own window_state member around and update it accordingly.
Chain up in GimpDisplayShell's window_state_event() impl.

app/display/gimpdisplayshell.c

@@ -643,6 +643,8 @@ gimp_display_shell_window_state_event (GtkWidget           *widget,
   GimpDisplayShell *shell = GIMP_DISPLAY_SHELL (widget);
   Gimp             *gimp  = shell->display->gimp;
 
+  GTK_WIDGET_CLASS (parent_class)->window_state_event (widget, event);
+
   shell->window_state = event->new_window_state;
 
   if (event->changed_mask & GDK_WINDOW_STATE_FULLSCREEN)

app/display/gimpimagewindow.c

@@ -30,6 +30,7 @@
 #include "gimpdisplayshell.h"
 #include "gimpimagewindow.h"
 
+#include "gimp-log.h"
 #include "gimp-intl.h"
 
 
@@ -57,6 +58,9 @@ static void      gimp_image_window_get_property (GObject      *object,
 
 static void      gimp_image_window_destroy      (GtkObject           *object);
 
+static gboolean  gimp_image_window_window_state (GtkWidget           *widget,
+                                                 GdkEventWindowState *event);
+
 
 G_DEFINE_TYPE (GimpImageWindow, gimp_image_window, GIMP_TYPE_WINDOW)
 
@@ -68,6 +72,7 @@ gimp_image_window_class_init (GimpImageWindowClass *klass)
 {
   GObjectClass   *object_class     = G_OBJECT_CLASS (klass);
   GtkObjectClass *gtk_object_class = GTK_OBJECT_CLASS (klass);
+  GtkWidgetClass *widget_class     = GTK_WIDGET_CLASS (klass);
 
   object_class->constructor        = gimp_image_window_constructor;
   object_class->finalize           = gimp_image_window_finalize;
@@ -76,6 +81,8 @@ gimp_image_window_class_init (GimpImageWindowClass *klass)
 
   gtk_object_class->destroy        = gimp_image_window_destroy;
 
+  widget_class->window_state_event = gimp_image_window_window_state;
+
   g_object_class_install_property (object_class, PROP_MENU_FACTORY,
                                    g_param_spec_object ("menu-factory",
                                                         NULL, NULL,
@@ -171,6 +178,17 @@ gimp_image_window_destroy (GtkObject *object)
   GTK_OBJECT_CLASS (parent_class)->destroy (object);
 }
 
+static gboolean
+gimp_image_window_window_state (GtkWidget           *widget,
+                                GdkEventWindowState *event)
+{
+  GimpImageWindow *window = GIMP_IMAGE_WINDOW (widget);
+
+  window->window_state = event->new_window_state;
+
+  return FALSE;
+}
+
 
 /*  public functions  */
 

app/display/gimpimagewindow.h

@@ -37,6 +37,8 @@ struct _GimpImageWindow
   GimpWindow       parent_instance;
 
   GimpUIManager   *menubar_manager;
+
+  GdkWindowState   window_state;
 };
 
 struct _GimpImageWindowClass