When merging files that contain the "159 '\u009f'" char, ArgumentException("The encoding is not supported.") is thrown.

Workaround:

Use PdfFormatProvider.

When applying a table or table cell border with no thickness specified, the border is exported with a default thickness value of zero. However, by specification, the default value should be 2.

Workaround: Create a border by specifying the thickness value. For example:

table.Borders = new TableBorders(new Border(thickness, BorderStyle.Single, new ThemableColor(Colors.Black)));

Trying to clone the Signature of a SignatureField leads to InvalidOperationException as the FieldName of the cloned signature is already set.

In WordsProcessing on import only the lower case CSS attributes are correctly imported. Upper case and mixed case are ignored and the default values are used.

Filter Selection dialog appears on the screen. 

Workaround: Open the file with Excel and save it as a new document.

When a TrueType font is defined, the mapping of character codes to glyph indices depends on the built-in cmap table mappings defined in the font and the Encoding property defined in the PDF dictionary.

However, the current implementation maps all characters with cmap tables for Microsoft Symbolic and Macintosh Roman, which causes incorrect mapping results, e.g. space characters are mapped to an Ê glyph.

The issue is also described in the following public item: TryGetCharCode for OpenTypeFont uses wrong cmap and returns wrong charcode.

Workaround: Change the font  of the TextBoxField's widget appearance:
foreach (var widget in field.Widgets)
{
    widget.TextProperties.Font = FontsRepository.Helvetica;
}