Add the 'page_changed' signal to GncEmbeddedWindow

This fixes an error message 'page_changed is invalid for instance of
type GncEmbeddedWindow' when you double click on the selected schedule
in the sx editor.

gnucash/gnome-utils/gnc-embedded-window.c

@@ -40,6 +40,13 @@
 #include "gnc-window.h"
 #include "dialog-utils.h"
 
+/** Names of signals generated by the embedded window. */
+enum
+{
+    PAGE_CHANGED,
+    LAST_SIGNAL
+};
+
 /* Static Globals *******************************************************/
 
 /** The debugging module that this .o belongs to.  */
@@ -93,6 +100,10 @@ GNC_DEFINE_TYPE_WITH_CODE(GncEmbeddedWindow, gnc_embedded_window, GTK_TYPE_BOX,
 #define GNC_EMBEDDED_WINDOW_GET_PRIVATE(o)  \
    ((GncEmbeddedWindowPrivate*)g_type_instance_get_private((GTypeInstance*)o, GNC_TYPE_EMBEDDED_WINDOW))
 
+/** A holding place for all the signals generated by the embedded window
+ *  code. */
+static guint embedded_window_signals[LAST_SIGNAL] = { 0 };
+
 /*  Display a data plugin page in a window. */
 void
 gnc_embedded_window_open_page (GncEmbeddedWindow *window,
@@ -179,7 +190,27 @@ gnc_embedded_window_class_init (GncEmbeddedWindowClass *klass)
 
     object_class->finalize = gnc_embedded_window_finalize;
     object_class->dispose = gnc_embedded_window_dispose;
-    
+
+    /**
+     * GncEmbeddedWindow::page_changed:
+     * @param window: the #GncEmbeddedWindow
+     * @param page: the #GncPluginPage
+     *
+     * The "page_changed" signal is emitted when a new page is
+     * selected in the notebook of a GncEmbeddedWindow. This can be
+     * used to to adjust menu actions based upon which page is
+     * currently displayed in a window.
+     */
+     embedded_window_signals[PAGE_CHANGED] =
+        g_signal_new ("page_changed",
+                      G_OBJECT_CLASS_TYPE (object_class),
+                      G_SIGNAL_RUN_FIRST,
+                      G_STRUCT_OFFSET (GncEmbeddedWindowClass, page_changed),
+                      NULL, NULL,
+                      g_cclosure_marshal_VOID__OBJECT,
+                      G_TYPE_NONE, 1,
+                      G_TYPE_OBJECT);
+
     LEAVE(" ");
 }
 

gnucash/gnome-utils/gnc-embedded-window.h

@@ -68,6 +68,10 @@ typedef struct
 {
     /** The parent class for an embedded window. */
     GtkBoxClass vbox;
+
+    /* callbacks */
+    void (*page_changed) (GncEmbeddedWindow *window,
+                          GncPluginPage *page);
 } GncEmbeddedWindowClass;