When unlocked GridPanel column ,the column display index was changed ?

I set gridpanel's some columns "Locked=true" in DesignTime,
Attachment 4840

and I set two or more columns to lock in runtime,
（my order of operations is first lock column '代码' ， then lock column '姓名' ）
Attachment 4839

but when i was unlocked the columns
（my order of operations is first unlock column '姓名' ， then unlock column '代码' ）
Attachment 4841
you will see the first unlocked column display in GridPanel's columns first index .
then the second unlocked column display in GridPanel's columns first index too.
the unlocked column's display index is unlike the GridPanle's first show.
i want after unlocked the column in runtime, display index like DesignTime ，
the column's display index must not changed.
how to do it ?
thanks~