The outlining feature is only available on certain types of terminals, usually those which also support the display of double-byte character sets.

%D=B		M		...
		I
		color-code
		B
		R
		W

The terminal command %D=B is used to control outlining.

Outlining (boxing) is the capability to generate a line around certain fields when they are displayed on the terminal screen. Drawing such "boxes" around fields is another method of showing the user the lengths of fields and their positions on the screen.

The %D=B command provides the following options:

Command	Function
%D=BM	This command causes all physically modifiable fields (AD=M or AD=A) to be displayed with outlining. If this command is repeated, this feature will be disabled again: in other words, it will return to the default state.
%D=BI	This command causes all intensified fields (AD=I) to be displayed with outlining.
%D=Bcolor-code	This command causes all fields of the specified color to be displayed with outlining. For valid color codes, see the session parameter CD.
%D=BB	This command causes "big boxes" to be generated: if several fields displayed underneath one another have identical display characteristics, one big box is drawn around all of them. Normally (if %D=BB is not specified) an individual box is drawn around each individual field.
%D=BR	This command causes all boxes to be reset; that is, no field will be displayed with outlining.
%D=BW	This command causes all windows which are to be displayed with frame (see the DEFINE WINDOW statement in the Statements documentation) to be displayed with outlining instead of frame.

When outlining is active, filler characters in modifiable fields are not displayed, because they serve the same purpose as outlining, namely showing the user the position and length of a field.

For further information, see Outlining - Terminal Command %D=B (in the Programming Guide).