The last column uses the width defined using Column.Width.
The OpenEnded property defines whether the last column is open-ended.
Using the OpenEnded property, the last displayed column can be defined as open-ended. An open-ended last column will display the complete text and graphics specified for the last (or only) column and never truncate any data. A fixed-width last column is defined with a specified width (see Column.Width) and any data which doesn't fit is truncated.