This is:

```
- [ ] a bug report
- [ ] a feature request
- [ ] **not** a usage question (ask them on https://stackoverflow.com/questions/tagged/phpspreadsheet or https://gitter.im/PHPOffice/PhpSpreadsheet)
```

### What is the expected behavior?


### What is the current behavior?


### What are the steps to reproduce?

Please provide a [Minimal, Complete, and Verifiable example](https://stackoverflow.com/help/mcve) of code that exhibits the issue without relying on an external Excel file or a web server:

```php
<?php

require __DIR__ . '/vendor/autoload.php';

// Create new Spreadsheet object
$spreadsheet = new \PhpOffice\PhpSpreadsheet\Spreadsheet();

// add code that show the issue here...
```
If this is an issue with reading a specific spreadsheet file, then it may be appropriate to provide a sample file that demonstrates the problem; but please keep it as small as possible, and sanitize any confidential information before uploading.

### What features do you think are causing the issue

- [ ] Reader
- [ ] Writer
- [ ] Styles
- [ ] Data Validations
- [ ] Formula Calulations
- [ ] Charts
- [ ] AutoFilter
- [ ] Form Elements

### Does an issue affect all spreadsheet file formats? If not, which formats are affected?


### Which versions of PhpSpreadsheet and PHP are affected?
