TAdvColumnGrid issue with ColumnHeaders[]

If I have a TAdvColumnGrid with, for example, 7 columns, and in code, I call:

  grid.HideColumn( 6 ;

If I then attempt this:
   s := grid.ColumnHeaders[6];

An exception is thrown. 

If I add a column header for a nonexistent eighth column, then there is no exception thrown. 

Sorry, the missing right parenthesis is the fault of my typing here. The actual code has no such failing.

grid.ColumnHeaders[] offers access to column header text of visible columns only;
If you would want access to the column header of non visible columns, I recommend to use

grid.AllCells[6,0] instead