Styles from property exportMenuHeaderStyle in kartik\grid\DataColumn are not applied for the header row of table when exporting to Excel 2007+ via ExportMenu widget. #285
2. Load the page with ExportMenu widget.
## Expected behavior and actual behavior
When I follow those steps, I see:
![2018-11-14_10-43-21](https://user-images.githubusercontent.com/6672987/48468681-9f4a7800-e7fd-11e8-8d9b-4409f92933d5.png)
I was expecting:
![2018-11-14_10-45-41](https://user-images.githubusercontent.com/6672987/48468691-a70a1c80-e7fd-11e8-8db8-fd7686e418ef.png)
I did not find the usages of exportMenuHeaderStyle for header cells in the generateHeader() method.
Also, in the generateBox() method common widget styles headerStyleOptions applied for all cells of header row.
## Environment
#### Browsers
- [x] Google Chrome
- [x] Mozilla Firefox
- [ ] Internet Explorer
- [ ] Safari
#### Operating System
- [x] Windows
- [ ] Mac OS X
- [x] Linux
- [ ] Mobile
#### Libraries
- jQuery version: v3.2.1
- yii2-export version: version 1.3.7
## Isolating the problem
- [ ] This bug happens [on the demos page](https://demos.krajee.com/export-demo)
- [x] The bug happens consistently across all tested browsers
- [x] This bug happens when using yii2-export without other plugins.
This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.
Prerequisites
master
branch of yii2-export.Steps to reproduce the issue
$gridColumns = [ 'id', [ 'class' => \kartik\grid\DataColumn::class, 'attribute' => 'name', 'exportMenuHeaderStyle' => [ 'fill' => [ 'color' => ['argb' => \PhpOffice\PhpSpreadsheet\Style\Color::COLOR_GREEN], ], ], ], 'description', ]; ?>
<?= ExportMenu::widget([ 'dataProvider' => $dataProvider, 'columns' => $gridColumns, 'fontAwesome' => true, 'target' => ExportMenu::TARGET_SELF, 'showConfirmAlert' => false, 'clearBuffers' => true, 'initProvider' => true, 'headerStyleOptions' => [ ExportMenu::FORMAT_EXCEL_X => [ 'fill' => [ 'color' => ['argb' => \PhpOffice\PhpSpreadsheet\Style\Color::COLOR_YELLOW], ], ], ], ]);