Syntax: ShiftTabs [0|1]
Abbreviation: SHT
sets the ShiftTabs flag. ShiftTabs has an effect only
when the Tabs flag is set, in which case an upper case ‘T’
appears in the status bar. When this flag and the Tabs flag are
both set, left and right Shift commands may use tab characters to
adjust leading white space. Otherwise only spaces are used. See Shift.