if (fPosition != null && !fPosition.isDeleted()) {
if (fPosition != null && !fPosition.isDeleted() && fViewer.getDocument() != null) {
	private void restorePosition() {		if (fPosition != null && !fPosition.isDeleted()) {			fViewer.setSelectedRange(fPosition.offset, fPosition.length);			fViewer.revealRange(fPosition.offset, fPosition.length);		}		fPosition= null;	}