tray icon behaviour

menu.rkt

@@ -6,6 +6,8 @@
   (provide wv-menu
            wv-menu-item
            is-wv-menu?
+           wv-menu? 
+           wv-menu-empty?
            wv-menu-set-callback!
            wv-menu-set-icon!
            wv-menu-set-title!
@@ -16,8 +18,6 @@
            wv-menu-item-id
            wv-menu-id
            )
-
-
   
   (define-struct ww-menu-item*
     (id [title #:mutable] [icon-url #:mutable] [callback #:mutable] [submenu #:mutable] [separator #:mutable])
@@ -37,6 +37,9 @@
 
   (define (wv-menu-id m)
     (ww-menu*-id m))
+
+  (define (wv-menu? mnu)
+    (is-wv-menu? mnu))
   
   (define (is-wv-menu? mnu)
     (if (ww-menu*? mnu)
@@ -61,10 +64,18 @@
       (when (symbol? (car items))
         (set! menu-id (car items))
         (set! items (cdr items)))
-      (when (list? (car items))
-        (set! items (car items)))
+      (if (null? items)
+        (set! items '())
+        (when (list? (car items))
+          (set! items (car items))))
       (make-ww-menu* menu-id items)))
 
+
+  (define (wv-menu-empty? menu)
+    (if (is-wv-menu? menu)
+        (null? (ww-menu*-items menu))
+        (error "wv-empty-menu?: argument is not a menu")))
+  
   (define (wv-menu-item id title
                      #:icon-url [icon-url #f]
                      #:callback [callback (lambda args #t)]