>I have a problem displaying data in a grid
>
>All the columns are set to display test in bold but when I click on any row I lose the bolding
>
>What causes this - it doesn't happen on my other grids

Play with each column's .sparse property. Whatever you set holds for all cells but the current, for which it seems to use default textbox. To test this, just try to set the font of everything in the grid to something serif, and I bet that in the selected cell you'll still see the stupid old AriaI.