OptionButton.TripleState Property (Outlook Forms Script)
Returns or sets a Boolean that determines whether the OptionButton supports the Null state. Read/write.
Syntax
expression .TripleState
expression A variable that represents an OptionButton object.
Remarks
True if the control clicks through three states, False if the control only supports two states, True and False (default).
Although the TripleState property exists on the OptionButton, the property does not affect the action of the control. Regardless of the value of TripleState, you cannot set the control to Null through the user interface.
Regardless of the property setting, the Null value can always be assigned programmatically to an OptionButton, causing that control to appear shaded.
When the TripleState property is True, a user can choose from the values of Null, True, and False. The null value is displayed as a shaded button.
When TripleState is False, the user can choose either True or False.
A control set to Null does not initiate the Click event.