When the Left/Right RepeatButton of the HorizontalScrollBar is clicked, the columns of DataGrid moved in the unit of some pixels.
This sometimes makes the left most column partial visible.
How to make the HorizontalScrollBar scroll in the unit of column?
The width of each column maybe different.
I know that sometimes it is impossible to makes the left most column complete show, because of the limit of the view and the width of other columns.