one editor destroy,another create,combo box can't open

mahuzi wrote:When one editor created in page,you click to open a toolbar combo box ,like font, fontsize etc.
destory the editor,then created another editor,and you click to open a toolbar combo box again,it can't be opend.
and I find this problem in ckeditor demo(sample) too.
demo:http://ckeditor.com/demo
you click a combo box in "Editor with all features" demo.
then you change to "Interface color" demo to click any combo box,it can't he opend.
firebug show some error:
"this.$ is undefined
http://ckeditor.com/apps/ckeditor/3.0.1 ... 1257207309
Line 11"
how to solve it?

再来个中文的描述：
当在一个页面中创建了一个编辑器实例以后，点击一个组合下拉框，比如字体，字体大小等。
移除这个编辑器再建一个新的实例，然后你再点工具栏中任意一个下来组合框，就打不开了。
这个现像在官方的例子和官方的下载包中的sample下面都会出现。
demo:http://ckeditor.com/demo
你点击 "Editor with all features" 例子中的一个下拉框，然后切换到"Interface color" 例子中再去点任意一个下拉框就点不开了。
firebug会报这样一个错误：
"this.$ is undefined
http://ckeditor.com/apps/ckeditor/3.0.1 ... 1257207309
Line 11"。
怎么才能解决这个问题呢？

从html dom分析来看，好像是多个编辑器共用的同样的下来框的iframe,destory一个以后，被共用的iframe也被删除了，而编辑器会以为那个iframe还存在，所以没有重新创建这个iframe