exception of ItemBox: index out of range

hi,
i edit a layout with itembox in backRetangle by MyGui_Layout_Editor which i got from svn and it is released,
when i load layout in my demo, and press itembox with mouse ,then there is an exception below:
[attachment=0]exception.jpg[/attachment]
but, it is fine when test in MyGui_Layout_Editor which i got from svn.

Then, i compile the source of project of MyGui_Layout_Editor, and do the same work, exception happens in my demo
and same to Editor itself.

Thanks