Similar to the Flex SDK grid, it is possible to add columns to Flexicious Ultimate at run time. Just use the addColumn method, passing in the FlexDataGridColumn instance.
There are a couple of methods, that come in handy:
1) distributeColumnWidthsEqually: If you wish to redistribute the column widths equally, call this method. Otherwise, when you add new columns, on basis of the columnWidthMode of each of the existing columns, the columnWidths are adjusted.
2) redraw/reBuild: These are methods that will basically drop all the components in the grid, and rebuild them. The redraw should be used when there is no change in the data provider. This method simply drops all the UI components and recreates them. The rebuild method on the other hand, should be used when there is an addition or removal from the data provider programmatically, or if there is a change to the structure of the dataprovider.