Bug 93400 LTK UI should provide official API for structural content in the preview page
org.eclipse.ltk.ui.refactoring/src/org/eclipse/ltk/internal/ui/refactoring/DefaultChangeElement.java
}
	
	public ChangePreviewViewerDescriptor getChangePreviewViewerDescriptor() throws CoreException {
		return ChangePreviewViewerDescriptor.get(fChange);
	}
	
	public void feedInput(IChangePreviewViewer viewer, List categories) throws CoreException {
		viewer.setInput(new ChangePreviewViewerInput(fChange));
	}
	
	/* non Java-doc
	 * @see ChangeElement#setActive
	 */
	public void setEnabled(boolean enabled) {
		fChange.setEnabled(enabled);
	}
	
	public void setEnabledShallow(boolean enabled) {
		fChange.setEnabledShallow(enabled);
	}
	
	/* non Java-doc
	 * @see ChangeElement.getActive
	 */
	public int getActive() {
		if (fChange instanceof CompositeChange || fChange instanceof TextEditBasedChange)
			return getCompositeChangeActive();
		else
			return getDefaultChangeActive();
	}