[suggestion] focus lost when there is error

[toylet [mozilla]]

1. Reply to a newsgroup message
2. news server refuse the message
    (owning to reply-to-quote ration error or whatever)
3. Composer reported the error and force users to click <OK>
4. Composer windows sent to background
    (behind the mozilla main window)

That's not convinient. users would need to hit the task far, and
look for that composer windows.