LockedColumns
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Prevent the user from selecting certain columns.

The C1FlexGrid has an AllowEditing property that can be used to prevent
users from editing cells in certain rows and columns. However, it
doesn't have properties to prevent users from selecting cells in certain
rows and columns.

This sample uses the BeforeSelChange event to prevent the user from 
selecting cells in certain columns. The code doesn't simply cancel 
invalid selections, it moves the cursor past the locked columns.