Click the Staff tool and double-click the
handle of the staff which should have flat beams. The Staff Attributes
dialog box appears.
Select Flat Beams from the Options section
of the dialog box. See Staff
Attributes dialog box for details. If you have a number of
staves to select Flat Beams for use the Global Staff Attributes plug-in.
This plug-in allows you to set up the staff attributes for a number of
staves at once. See Global
Staff Attributes Plug-in.