Returns <code>true</code> to indicate that the receiver's close button should be shown.
Otherwise return <code>false</code>. The initial value is defined by the style (SWT.CLOSE)
that was used to create the receiver.
@return <code>true</code> if the close button should be shown
@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>
Returns <code>true</code> to indicate that the receiver's close button should be shown. Otherwise return <code>false</code>. The initial value is defined by the style (SWT.CLOSE) that was used to create the receiver.
@return <code>true</code> if the close button should be shown
@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>
@since 3.4