The OBJECT SET THREE STATES CHECKBOX command modifies, for the current process, the "Three-States" property of the checkbox(es) designated by the object and * parameters.
The "Three-states" option allows the additional "semi-checked" state to be used for checkboxes. For more information, refer to Three-States check box in the Design Reference manual.
Passing the optional * parameter indicates that the object parameter is an object name (string). If you do not pass this parameter, it indicates that the object parameter is a field or variable. In this case, you pass a field or variable reference instead of a string (field or variable object only).
This command only applies to checkboxes associated with variables, and not to Boolean fields that are represented as checkboxes.
In the threeStates parameter, pass True to enable the "three states" mode, or False to disable it.