Set the control that appears in the top center of the pane.
Typically this is a toolbar.
The topCenter is optional. Setting the topCenter to null will remove it from
the pane - however, the creator of the topCenter must dispose of the topCenter.
*
@param topCenter the control to be displayed in the top center or null
*
@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>
<li>ERROR_INVALID_ARGUMENT - if the control is not a child of this ViewForm</li>
</ul>
Set the control that appears in the top center of the pane. Typically this is a toolbar. The topCenter is optional. Setting the topCenter to null will remove it from the pane - however, the creator of the topCenter must dispose of the topCenter. * @param topCenter the control to be displayed in the top center or null * @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> <li>ERROR_INVALID_ARGUMENT - if the control is not a child of this ViewForm</li> </ul>