Question:

"I've discovered another issue that had me completely baffled for 2 days, but I think I've found the cause.  I was adding columns to my datagrid, but they would not display in the grid after compilation of my code. Also, if I changed a headerText value, the column would disappear after compilation when I ran my code"

 

Answer: The solution is simple:

If you see this, more than likely you have column preferences persisted. Clear your preferences, using Save Preferences -> Clear Preferences, OR clear your shared objects like defined below:

http://blog.ickydime.com/2008/12/how-to-delete-flash-shared-objects.html

 

Also, in case you add new columns, or remove columns, your users who have preferences saved may not see the updated columns. To combat this, just provide a new preferencePersistenceKey, and the grid will be treated as a new grid from a preference persistence perspective.