Bitfields for TopView field type:
Bit(s)	Description	)
 7,6	field class
	00 inactive (non-entry) field
	01 echos keystrokes input to make menu selection
	10 fill-in field
	11 select field
 5	field can be filled by broadcast write (F7h opcode)
 4	reserved
 3	reserved
 2	reserved
 1	set if field selected
 0	set if field modified
SeeAlso: #00444