[]as3分包，如果在ui编辑器IDE里导入了类runtime，在分包里就会报错。这个怎么处理。

Uncaught ReferenceError: MailPanel is not defined
    at MailWin.__proto.createChildren (Nxsg.max.js:71310)
    at MailWin.Component (Nxsg.max.js:52200)
    at MailWin.Box (Nxsg.max.js:58163)
    at MailWin.View (Nxsg.max.js:62736)
    at MailWinUI (Nxsg.max.js:71304)
    at new MailWin (eval at __proto.loadJs (Nxsg.max.js:52044), <anonymous>:10904:20)
    at MailLockWin.__proto.setWin (Nxsg.max.js:52913)
    at new MailLockWin (eval at __proto.loadJs (Nxsg.max.js:52044), <anonymous>:866:9)
    at Nxsg.__proto.loadJs (Nxsg.max.js:52046)
    at EventHandler.__proto.runWith (Nxsg.max.js:20173)