dataGrid in popup doesn't add Header row first time shown

Datagrid in a popup (gridDropDownContainer) At popup, i'm populating the grid, then adding a header row (which has a SUM formula added to each column). The first time the grid is shown, the header row is not added...the code runs, no errors, but the header is not there. The second time it runs, it is shown. IF I show the popup, and THEN populate the grid and add the extra column, then it does show up the first and subsequent times... however, it's really really slow, because I'm setting column widths (when the grid isn't shown while setting columns widths, its very fast...)

You can probably get things to display quicker by adding grid.BeginUpdate() and grid.Binder.SuspendBinding() before you populate the grid, and the grid.Binder.ResumeBinding() and grid.EndUpdate() after you finish the population code.