I have a RadGrid in a UpdatePanel (standard .net one) which in turn is in a modal pop up. When the popup is first shown the grid displays correctly however if the popup is closed and reopened then the styling for the grid is missing, there are no gridlines. If I look at the CSS loaded for the page (using FireFox webdeveloper plugin) I can see that the CSS for the radGrid is missing on the second load, even though CSS for other rad components are there. Any idea what might cause this? The gird has visible="false" when the popup is opened and is only displayed after the user presses a button in the popup.