title: Why Apache POI xlsx wrap text not working?
body: <p>I have a cell that should contain rather long text with multiple \n.
  I'm using <code>setWrapText(true)</code> on a cell style object but it seems not working.
  I still can only see the first line of a cell text. 
  Here is the code I'm using </p>
  
  <pre><code>CellStyle mainHeaderCellStyle = wb.createCellStyle();
  mainHeaderCellStyle.setFillForegroundColor(IndexedColors.GREY_25_PERCENT.getIndex());
  mainHeaderCellStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);
  mainHeaderCellStyle.setWrapText(true);
  
  Cell headersCell = infoRow.createCell(cellIndex);
  headersCell.setCellStyle(mainHeaderCellStyle);
  headersCell.setCellValue(mainHeader);
  </code></pre>
  
  <p>But the header cell (colored in grey) is still like this
  <a href="https://i.stack.imgur.com/PgTNR.png" rel="nofollow noreferrer">XLSX page with header</a></p>
  
  <p>This is the text when I double click the cell
  <a href="https://i.stack.imgur.com/WoLL0.png" rel="nofollow noreferrer">XLSX page with clicked header</a></p>