Include windows in window list containing empty value for 'window_typ…

…e'. Addresses #43

src/windows/WindowPage.vala

@@ -165,7 +165,7 @@ namespace Ilia {
         }
 
         private void traverse_nodes (TreeReply node) {
-            if (node.ntype == "con" && node.window_type == "normal") {
+            if (navigable_window(node)) {
                 var pixbuf = load_icon_from_app_name (icon_theme, node.windowProperties.clazz, icon_size);
 
                 model.append (out iter);
@@ -190,6 +190,10 @@ namespace Ilia {
             }
         }
 
+        private bool navigable_window(TreeReply node) {
+            return node.ntype == "con" && (node.window_type == "normal" || node.window_type == "");
+        }
+
         // Automatically set the first item in the list as selected.
         private void set_selection () {
             Gtk.TreePath path = new Gtk.TreePath.first ();