At the moment, you can not rename a file while it is downloading or a folder with any file in it that is downloading (in the Properties -> Files view of a torrent). The reason is that your edit textbox always loses focus when the status is updated. This is BTW the main reason why I consider "inline editing" not to be a good idea.
But I'm afraid you will not drop inline editing just because of this, will you ?
So, I have another idea: suppress all status updates while an inline editing textbox is open.
thanks,
tuxolero