Minimized Overlines

Use this command (Home tab > Spreadsheet Display group, or in classic view, the Home menu) to combine spreadsheet sort levels into a single column.

Sort levels are combined if there is a ü next to the command.

Tips:

When you minimize overlines, the single column that appears is labeled Spreadsheet Level. You can change this name in the column properties.
Minimize overline columns is also an option for the Spreadsheet report.