To change the width of the tab character:
Select "Window" > "Preferences" from the menu bar. The Preferences dialog box appears.
Select "COBOL" > "Editor" in the left pane. The Editor page is displayed.
Click the "Reference Format" tab.
Specify 4 or 8 as the tab width value for "Tab width".
Note
By default, 4 is set for the tab width value.