Mark,
The problem was setting the column's sparse property equal to .f. instead of .t. in my LoadColumn method by default. This is documented in the help.
If a column's Sparse property is set to False (.F.), the column will not be highlighted, when the grid's HighlightStyle property is set to 1 or 2.
BTW, the rowhighlighting works fine using NEWOBJECT to add columns to the grid rather than ADDCOLUMN.
Thanks for your time.
>Not wanting to wade through your code here, let's start with the simplest question and work from there. Have you set the HighlightStyle property of the grid to 2? If this is not what you had in mind, then we can start over with your problem.