Currently, this missing functionality may be workaround by either drawing the headers and footers with FixedContentEditor or by using RadWordsProcessing PDF export.

When creating a GradientStop, an alpha channel of the color could be applied. However, this setting is not respected it the result document and the gradient is with full opacity.

Steps to reproduce:
1. Create a gradient with an alpha channel:

RadFixedDocument document = new RadFixedDocument();
RadFixedPage page = document.Pages.AddPage();
FixedContentEditor containerEditor = new FixedContentEditor(page);

LinearGradient linearGradient = new LinearGradient(new Point(0, 0), new Point(30, 30));
linearGradient.GradientStops.Add(new GradientStop(new RgbColor(10, 0, 207, 0), 0));
linearGradient.GradientStops.Add(new GradientStop(new RgbColor(10, 0, 102, 204), 1));

containerEditor.GraphicProperties.FillColor = linearGradient;
containerEditor.DrawRectangle(new Rect(10, 10, 48, 29));

2. Export the document to PDF

Observed: The alpha channel is not respected and the gradient is with full opacity

Adding a table with the same code leads to different results 

When adding 10 identical tables onе or more have missing rows at the bottom. The seems to be caused by the text measurement. 

Culture on generating computer: de-DE

• Format string: #.##0,00  -> Output correct: 1,234,567.89 (on US) and 1.234.567,89 (on German)
• Format string: #,##0.00  -> Output incorrect: 1,234,567.89 (on US) and 1.234.567,89 (on German)
• Format string: #.##0,0  -> Output incorrect: 1234567.8901 (on US) and 1234567,8901 (on German)
• Format string: #,##0.0  -> Output incorrect: 1,234,567.8 (on US) and 1.234.567,8 (on German)

The first string is an in-built string and is exported correctly. The other three strings are custom (not part of the in-built collection), are not converted to invariant culture and do not produce correct results when the file is opened in Excel.

When the <sectPr> element is not defined as the last child element but appears in different position of the <body> of the document, the content after <sectPr> is not imported. 

Although some applications handle this case, according to the Office Open XML specification, the sectPr element must be the last element inside the <body>.

Exception when there are merge fields in the header/footer and one performs mail merge: 

Unable to cast object of type 'Telerik.Windows.Documents.Flow.Model.Header' to type 'Telerik.Windows.Documents.Flow.Model.BlockBase

If Paragraph has applied style, and this style has associated list, and the paragraph is removed from the list locally, then on import the paragraph is added to the list.

The additional numbering could be removed from the paragraph by changing its style:

foreach (var p in this.document.EnumerateChildrenOfType<Paragraph>())
{
    if (p.ListLevel == 0)
    {
        var style = new Telerik.Windows.Documents.Flow.Model.Styles.Style("NoListStyle", StyleType.Paragraph);
        style.ParagraphProperties.CopyPropertiesFrom(this.document.StyleRepository.GetStyle(p.StyleId).ParagraphProperties);
        style.ParagraphProperties.ListId.LocalValue = null;
        style.ParagraphProperties.ListLevel.LocalValue = null;
        p.StyleId = "NoListStyle";
    }
}

Import the following HTML content:

<ol type="a">
<li>
<div><p>WordsProcessing</p>
</div></li>
<li>
<div>
<p>SpreadProcessing</p>
</div>
</li>
<li>
<div>
<p>PdfProcessing</p>
</div>
</li>
</ol>

The following error occurs:

When list level items are empty - <li></li> - they are not imported as empty paragraphs in list. The expected is that a Paragraph, associated to a list to be imported.

Unexpected table content indentation during PDF export when cells lack explicit margins and do not inherit table-level margins.

Manual Workaround Before PDF Export:

Preserve direct cell overrides; materialize table-default padding only for cells with no local padding:

foreach (var section in document.Sections)
{
    foreach (var block in section.Blocks)
    {
        if (!(block is Table table))
        {
            continue;
        }

        foreach (var row in table.Rows)
        {
            foreach (var cell in row.Cells)
            {
                if (!cell.Properties.Padding.HasLocalValue)
                {
                    cell.Padding = table.TableCellPadding;
                }
            }
        }
    }
}

Exception "Format string is not in the correct format" is thrown when importing a file with the following format string: "US$"#,##0.0"m";($#,##0.0)

The exception is thrown in the ValidateDateTimeFormatDescriptor method. 

Excessive text wrapping and row heights due to columns collapsing to excessively narrow widths when the total column width exceeds the table width.

Regression in versions after 2026.3.810.

Workaround: Manually readjust the column Width values.