pr-menu-char-width

pr-menu-char-width is a variable defined in `printing.el'.
Its value is

1

Documentation:
Specify menu char width in pixels.

This variable is used to guess which horizontal position should be locked the
menu, so don't forget to adjust it if menu position is not ok.

See also `pr-menu-lock' and `pr-menu-char-height'.

You can customize this variable.