Adds a selection listener. A Selection event is sent by the widget when the
user changes the selection.
<p>
When <code>widgetSelected</code> is called, the event x and y fields contain
the start and end caret indices of the selection.
<code>widgetDefaultSelected</code> is not called for StyledTexts.
</p>
@param listener the listener which should be notified when the user changes the receiver's selection
@exception IllegalArgumentException <ul>
<li>ERROR_NULL_ARGUMENT - if the listener is null</li>
</ul>
@exception SWTException <ul>
<li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
<li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
</ul>
Adds a selection listener. A Selection event is sent by the widget when the user changes the selection. <p> When <code>widgetSelected</code> is called, the event x and y fields contain the start and end caret indices of the selection. <code>widgetDefaultSelected</code> is not called for StyledTexts. </p>
@param listener the listener which should be notified when the user changes the receiver's selection
@exception IllegalArgumentException <ul> <li>ERROR_NULL_ARGUMENT - if the listener is null</li> </ul> @exception SWTException <ul> <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> </ul>
@see SelectionListener @see #removeSelectionListener @see SelectionEvent