Marks the receiver as visible if the argument is <code>true</code>,
and marks it invisible otherwise.
<p>
If one of the receiver's ancestors is not visible or some
other condition makes the receiver not visible, marking
it visible may not actually cause it to be displayed.
</p>
@param visible the new visibility state
@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>
Marks the receiver as visible if the argument is <code>true</code>, and marks it invisible otherwise. <p> If one of the receiver's ancestors is not visible or some other condition makes the receiver not visible, marking it visible may not actually cause it to be displayed. </p>
@param visible the new visibility state
@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>