CS4 Actionscript 2 datagrid problem when masked

Hello

I’m working in CS4 but need to produce Flash in actionscript 2.

I put a datagrid on the stage and then in actionscript iterate through some data to create the correct number of columns with the correct names in the datagrid. This works fine. However, for various reasons, I need to put a mask over the entire stage.

When the layers that include the datagrid are masked, the datagrid no longer shows the column titles although the correct number of columns is shown.

Has anyone come across this before and knows a work around?

Thanks for your help
Chris