Returns <code>true</code> if the widget has been disposed,
and <code>false</code> otherwise.
<p>
This method gets the dispose state for the widget.
When a widget has been disposed, it is an error to
invoke any other method using the widget.
</p>
@return <code>true</code> when the widget is disposed and <code>false</code> otherwise
Returns <code>true</code> if the widget has been disposed, and <code>false</code> otherwise. <p> This method gets the dispose state for the widget. When a widget has been disposed, it is an error to invoke any other method using the widget. </p>
@return <code>true</code> when the widget is disposed and <code>false</code> otherwise