If set to true, this will make the button act like an inline button so the width is determined by the button's content. If set to false, the button width is the full width of its container, regardless of the content.
Note: This property is only valid if the displayAs property is set to 'Button' and will be ignored otherwise.
False - the button is as wide as its container.
True, False, or any valid XPath expression that returns a boolean value.