Bug 49182 What should canceling setRawClasspath do ?
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/VariableBlock.java
fVariablesList.setDialogFieldListener(adapter);
		fVariablesList.setLabelText(NewWizardMessages.getString("VariableBlock.vars.label")); 
		fVariablesList.setRemoveButtonIndex(2);
		
		fVariablesList.enableButton(1, false);
		
		fVariablesList.setViewerSorter(new ViewerSorter() {
			public int compare(Viewer viewer, Object e1, Object e2) {
				if (e1 instanceof CPVariableElement && e2 instanceof CPVariableElement) {
					return ((CPVariableElement)e1).getName().compareTo(((CPVariableElement)e2).getName());
				}
				return super.compare(viewer, e1, e2);
			}
		});
		refresh(initSelection);
	}
	
	public boolean hasChanges() {
		return fHasChanges;
	}
	
	public void setChanges(boolean hasChanges) {
		fHasChanges= hasChanges;
	}
	
	
	private String[] getReservedVariableNames() {
		return new String[] {
			JavaRuntime.JRELIB_VARIABLE,
			JavaRuntime.JRESRC_VARIABLE,