private Object lookupItem(String pattern) {
		Object selectedItem = model.getSelectedItem();
		// only search for a different item if the currently selected does
		// not match
		if (selectedItem != null
				&& startsWithIgnoreCase(selectedItem.toString(), pattern)) {
			return selectedItem;
		} else {
			// iterate over all items
			for (int i = 0, n = model.getSize(); i < n; i++) {
				Object currentItem = model.getElementAt(i);
				// current item starts with the pattern?
				if (startsWithIgnoreCase(currentItem.toString(), pattern))
					return currentItem;
			}
		}
		// no item starts with the pattern => return null
		return null;
	}