XlsFormatProvider: InvalidOperationException is thrown when importing a document with an unsupported BIFF record.

Workaround: Re-save the file with Excel before importing it.

The issue is reproducible with PDF form fields and setting Polish characters to the text fields: e.g. "ęóąśłżźćń" 

Edit mode in RadPdfViewer:

Exit edit mode:

Here is a sample code snippet for reproducing the case without UI:

            PdfFormatProvider provider = new PdfFormatProvider();
            RadFixedDocument document = provider.Import(File.ReadAllBytes("file.pdf"), TimeSpan.FromSeconds(10));

            foreach (RadFixedPage page in document.Pages)
            {
                foreach (Annotation annotation in page.Annotations)
                {
                    if (annotation.Type == AnnotationType.Widget)
                    {
                        Widget widget = (Widget)annotation;
                        var field = widget.Field as TextBoxField;
                        if (field != null) 
                        {
                            field.Value = "ęóąśłżźćń.";
                        }
                    }
                }
            }
            string outputFilePath = "result.pdf";
            File.Delete(outputFilePath);
            File.WriteAllBytes(outputFilePath, provider.Export(document, TimeSpan.FromSeconds(10)));
            Process.Start(new ProcessStartInfo() { FileName = outputFilePath, UseShellExecute = true });

After merging several PDF documents, some pages are blank indicating the following error:

When using Telerik Document Processing (PdfProcessing) for embedding Factur-X invoices, the produced PDF document is Non‑compliant with PDF-AF / Factur‑X according to the following validator: 

https://www.superpdp.tech/outils/validateur-facture-electronique/ 

This is preserved in the xml once saved from MS Excel:

Add support for creating Tables and applying tables styles (predefined ones or custom).

Add support for VML shapes.

Related: Add support for Shape Group.

Shape Group is used to collect shapes and groups so they can be positioned and transformed as a single unit. A group contains group, shapetype, shape, pre-defined shape - arc, curve, image, line, oval, polyline, rect, roundrect - and lock elements.

When the object is serialized out as XML, its qualified name is v:group.

Provide the ability to work with images in headers/footers of a worksheet. Note that large images put in headers are visualized as watermarks on printing/exporting to PDF.
Watermark in Excel: https://support.office.com/en-us/article/add-a-watermark-in-excel-a372182a-d733-484e-825c-18ddf3edf009
 

Currently, the numbers in a CSV file are parsed as numbers, and the leading zeros are lost. In MS Excel, leading zeros could be preserved when the values are imported as text using the more sophisticated text import wizard (http://www.upenn.edu/computing/da/bo/webi/qna/iv_csvLeadingZeros.html ).

Workaround: The values could be extracted using a third-party (or custom) CSV parser, and inserted manually into the model, using CellSelection.SetValueAsText method (http://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/working-with-cells/cell-value-types.html ).