Been having problems for my itemRenderers in datagrids. I am using Button control as a itemRenderer and setting their visibility based on their labels. Somehow, the buttons becomes visible when my DataGrid dataprovider is changed.
The reference below solved my problem. I needed to place my logic to set the visible variable in the right place. Rest of the article touches on efficiency.
Reference: Peter Ent - itemRenderers: Part 5: Efficiency