I have a grid with many columns in it. The first two have display="false". They're IDs used to create links for other columns in the Grid_ItemDataBound event. Anyway, The report shows correctly when created with the browser maximized, but if I restore and then maximize again, the hidden columns show up. When they work, the TH has style="display:none" and after restoring and maximizing the style is gone. This is happening in 2 out of maybe 50 reports and most of them have hidden fields, so it's probably related to the layout of these particular grids.