Sets the widget font.
<p>
When new font is null, the font reverts
to the default system font for the widget.
*
@param font the new font (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>
</ul>
Sets the widget font. <p> When new font is null, the font reverts to the default system font for the widget. * @param font the new font (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> </ul>