Returns the control that is used to fill the client area of
the tab folder when the user selects the tab item. If no
control has been set, return <code>null</code>.
<p>
@return the control
@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 the control that is used to fill the client area of the tab folder when the user selects the tab item. If no control has been set, return <code>null</code>. <p> @return the control
@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>