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/PseudoLanguageChangeElement.java
viewer.setInput(null);
		}
	}
	
	public void setEnabled(boolean enabled) {
		for (Iterator iter= fChildren.iterator(); iter.hasNext();) {
			ChangeElement element= (ChangeElement)iter.next();
			element.setEnabled(enabled);
		}
	}
	
	public void setEnabledShallow(boolean enabled) {
		
	}
	
	public int getActive() {
		Assert.isTrue(fChildren.size() > 0);
		int result= ((ChangeElement)fChildren.get(0)).getActive();
		for (int i= 1; i < fChildren.size(); i++) {
			ChangeElement element= (ChangeElement)fChildren.get(i);
			result= ACTIVATION_TABLE[element.getActive()][result];
			if (result == PARTLY_ACTIVE)
				break;
		}
		return result;
	}
	
	/* non Java-doc
	 * @see ChangeElement.getChildren
	 */