Frozen cells remain on the screen when the user scrolls the control (like fixed cells), but they are selectable and editable (like scrollable cells). They are painted using the CellStyleCollection.Frozen style.

To freeze rows or columns at runtime, the mouse must be near the edge of the frozen area. The mouse pointer will then change into a 'freeze' pointer (looks like a padlock) and the user can drag the frozen boundary to a new row or column.

Reference

C1FlexGrid Class
C1FlexGrid Members