Create the TextChangedEvent to be used by the StyledTextContent implementor. <p>
the display where the event occurred
the widget that issued the event
the time that the event occurred.
a field for application use
Returns the name of the event. This is the name of the class without the module name.
Returns a string containing a concise, human-readable description of the receiver.
This event is sent by the StyledTextContent implementor when a change to the text occurs.
@see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>