A checkbox is a labelled box which is either on (checkmark is visible) or off (no checkmark).
Creates a checkbox with a text or bitmap label, or without a label.
If func is not null, it is called whenever the checkbox state is changed by the user.
If label is not null, it is used as the label for the checkbox. If label is null, the checkbox is created without a label.
The parameters x and y are used to specify an absolute position for the checkbox within the panel; if -1 is provided, a default position will be assigned such that the checkbox is placed next to the last item inserted into the panel. If width or height is -1, an appropriate size will be used for the checkbox based on the checkbox label.
The style argument is reserved for future use.
The name argument is used to associate a name with the checkbox, allowing the application user to set X Windows resource values for each individual checkbox.