>Always I write a new option on combo and move the focus to next column of the grid, the content of combo that I just have typed is cleared. After saving and refresh, the content of combo is showed.
>
>Why the content of combo is cleared? What am I doing wrong?

If you add a new item, you need to add it to array as well.

See this thread Re: Combo box just won't keep hand entered text Thread #987581