I have 2.4.4.7 and may be a similar issue.
Using a TDBAdvGrid that displays a query of approximately 200 records and showing approximately 30 in the grid. I have grdTestRanges.FixedCols:=3; The grid scrolls fine when using the mousewheel and scroll bar in the grid are used, but not when the up and down arrow are used. When a cell is selected in the last visible row of the grid and the down arrow is pressed, the fixed col data does not change but the non-fixed columns correctly scroll to the next record.
If I set the FixedCols := 1 (the marker), mouse and keyboard scrolling work properly.
I would like to use the FixedCols := 3 because if the user uses the right arrow, I wish to keep those columns visible in the grid.