# Boolean (filter, event)

A Boolean, on-off interactor.

Value `GP`
  (Boolean, `FALSE`)
  The current state.
MenuStyle
  (Boolean, `FALSE`)
  When set, the interactor should be a child of a `Menu`, in which case it will react on the upclick. Otherwise, it reacts on the downclick.

Feedback choices (mutually exclusive):

CheckBox
  (Boolean, `TRUE`)
  Give feedback with a ``check-box'' icon.
CheckMark
  (Boolean, `FALSE`)
  Give feedback with a ``check-mark'' icon.
Inverting
  (Boolean, `FALSE`)
  Give feedback by displaying a border around the child `VBT`.

Behavior
  If `CheckBox` (the default) is set, FormsVBT adds a three-dimensional check-box icon to the left of its child. To indicate a false value, the check-box is raised and empty; to indicate a true value, the check-box is lowered and filled-in. Any click on the check-box or on the child toggles state and generates an event on the upclick. `CheckMark` causes a different set of bitmaps to be used to indicate state. `Inverting` causes no bitmaps to be used. Actually, ``inverting'' is a (historical) misnomer: on a non-monochrome display, a three-dimensional shadow is put around the child, and the shadow is raised (when false) and lowered (when true).
Shape
  When `Inverting` is false, the shape of this interactor is the shape of its child, plus 16 pixels wider on the west side. When `Inverting` is true, the shape of the interactor is the shape of the child plus the shadow.
Notes
  The `CheckMark` property, in conjunction with `MenuStyle`, can be used to implement the Macintosh-style ``checks'' on menu items. However, because the check-mark is put to the left of its child, menu elements will look misaligned if some elements are `MButton`s and others are `Boolean`s with check-marks.
See Also
  Choice and Radio