Locking a column “locks” that column and all other columns to the left of it into one static pane, and all columns to the right into another pane through which you can scroll horizontally.
A lock works only until you move away from the entity view. You can’t save it to the default or custom view.
(To lock a column configuration) On the right side of the column heading, click , and then select Lock Column.
(To unlock a column configuration) On the right side of any column heading in the locked column set, click , and then select Unlock Column.