button_release_event

[Jan <janjakon mail ru>]

Hello.

I apologize for my importunity.
But I can not find any eyeful information in documentation.

I try to draw line from point where user press left mouse button.

I have follows initialization code:

GtkWidget *topLevelWindow=gtk_window_new(GTK_WINDOW_TOPLEVEL);

g_signal_connect(G_OBJECT(topLevelWindow), "delete_event",
                 G_CALLBACK(OnDelete), NULL);
g_signal_connect(G_OBJECT(topLevelWindow),
                 "destroy",  G_CALLBACK(OnDestroy),
                 NULL);
GtkWidget *canvas=gtk_drawing_area_new();
g_signal_connect(G_OBJECT(canvas), "expose_event",
                 G_CALLBACK(OnDraw), NULL);
g_signal_connect(G_OBJECT(GTK_WINDOW(topLevelWindow)),
                 "button_release_event", G_CALLBACK(OnButtonReleaseEvent),
                 NULL);
gtk_container_add(GTK_CONTAINER(topLevelWindow), canvas);
gtk_widget_show(canvas);
gtk_widget_show(topLevelWindow);

And have follow OnButtonReleaseEvent:

gboolean OnButtonReleaseEvent(GtkWidget *widget, GdkEventExpose *event, gpointer data)
{
  g_print("Release Event!\n");
  return TRUE;
}

I clicked and clicked on window of my application 
and there are no "Release Event!".

Why so?