@noindent
Every character not part of the sub-formula @samp{b} has been changed
-to a dot. The @samp{*} next to the line number is to remind you that
+to a dot. (If the customizable variable
+@code{calc-highlight-selections-with-faces} is non-nil, then the characters
+not part of the sub-formula are de-emphasized by using a less
+noticeable face instead of using dots. @pxref{Displaying Selections}.)
+The @samp{*} next to the line number is to remind you that
the formula has a portion of it selected. (In this case, it's very
obvious, but it might not always be. If Embedded mode is enabled,
the word @samp{Sel} also appears in the mode line because the stack
@noindent
@kindex j d
@pindex calc-show-selections
+@vindex calc-highlight-selections-with-faces
+@vindex calc-selected-face
+@vindex calc-nonselected-face
The @kbd{j d} (@code{calc-show-selections}) command controls how
selected sub-formulas are displayed. One of the alternatives is
illustrated in the above examples; if we press @kbd{j d} we switch
. . . . 2 x + 1
@end group
@end smallexample
+If the customizable variable
+@code{calc-highlight-selections-with-faces} is non-nil, then the
+non-selected portion of the formula will be de-emphasized by using a
+less noticeable face (@code{calc-nonselected-face}) instead of dots
+and the selected sub-formula will be highlighted by using a more
+noticeable face (@code{calc-selected-face}) instead of @samp{#}
+signs. (@pxref{Customizing Calc}.)
@node Operating on Selections, Rearranging with Selections, Displaying Selections, Selecting Subformulas
@subsection Operating on Selections
Calc is controlled by many variables, most of which can be reset
from within Calc. Some variables are less involved with actual
-calculation, and can be set outside of Calc using Emacs's
+calculation and can be set outside of Calc using Emacs's
customization facilities. These variables are listed below.
Typing @kbd{M-x customize-variable RET @var{variable-name} RET}
will bring up a buffer in which the variable's value can be redefined.
and @code{calc-embedded-open-close-plain-alist}.
@end defvar
+@defvar calc-highlight-selections-with-faces
+@defvarx calc-selected-face
+@defvarx calc-nonselected-face
+The variable @code{calc-highlight-selections-with-faces}
+determines how selected sub-formulas are distinguished.
+If @code{calc-highlight-selections-with-faces} is nil, then
+a selected sub-formula is distinguished either by changing every
+character not part of the sub-formula with a dot or by changing every
+character in the sub-formula with a @samp{#} sign.
+If @code{calc-highlight-selections-with-faces} is t,
+then a selected sub-formula is distinguished either by displaying the
+non-selected portion of the formula with @code{calc-nonselected-face}
+or by displaying the selected sub-formula with
+@code{calc-nonselected-face}. (@pxref{Displaying Selections}.)
+@end defvar
+
@defvar calc-multiplication-has-precedence
The variable @code{calc-multiplication-has-precedence} determines
whether multiplication has precedence over division in algebraic