InvalidOperationException is thrown when exporting font that is available but not used.

The stack trace is as follows:
   at System.Linq.Enumerable.Max(IEnumerable`1 source)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Fonts.Cid.CidSet.CopyPropertiesFrom(IPdfExportContext context, FontBase font)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Fonts.CidFontDescriptor.CalculateCidSet(IPdfExportContext context, CidFontBase font)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Fonts.CidFontDescriptor.<>c__DisplayClass34.<CopyPropertiesFrom>b__30()
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Utilities.PdfObjectsExtensions.ToPrimitive[P,T](PdfProperty`1 pdfProperty, Func`2 convertToPrimitive, Func`1 getDefaultValue)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Fonts.CidFontDescriptor.CopyPropertiesFrom(IPdfExportContext context, FontBase font)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Fonts.CidFontObject.CopyPropertiesFromOverride(IPdfExportContext context, FontBase font)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Fonts.CidFontObject.CopyPropertiesFrom(IPdfExportContext context, FontBase font)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Fonts.Type0FontObject.CopyPropertiesFromOverride(IPdfExportContext context, FontBase font)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Export.PdfExporter.WriteFontsFromContext(PdfWriter writer, IPdfExportContext context)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Export.PdfExporter.Export(IRadFixedDocumentExportContext context, Stream output)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.PdfFormatProvider.ExportOverride(RadFixedDocument document, Stream output)
   at Telerik.Windows.Documents.Common.FormatProviders.FormatProviderBase`1.Export(T document, Stream output)

The exception is thrown with the message "Password is not correct" even when the user password is correct. This issue occurs for specific encryption algorithm parameters only.

This includes loading form fields data from FDF file and saving the form fields data to FDF file.

This exception seems to be related to AES algorithm PaddingMode property. 

The signature field preserves information about the time of signing through the TimeOfSigning property of Signature.Properties. However, the DateTime object doesn't keep info about the time zone the document has been signed in. Some customers need to obtain this information.

While signing a document in Adobe Reader, the users can lock the document fields from editing. Expose a similar functionality.

The feature is described by the FieldMDP transform method, described on page 736 from the Pdf Reference 1.7

When merging documents` pages using the PdfStreamWriter the Form Fields are not copied:

using (PdfStreamWriter fileWriter = new PdfStreamWriter(File.OpenWrite(document2Name)))
{
	// Iterate through the files you would like to merge 
	for (int i = 0; i < 2; i++)
	{
		// Open each of the files 
		using (PdfFileSource fileToMerge = new PdfFileSource(File.OpenRead(document1Name)))
		{
			// Iterate through the pages of the current document 
			foreach (PdfPageSource pageToMerge in fileToMerge.Pages)
			{
				// Append the current page to the fileWriter, which holds the stream of the result file 
				fileWriter.WritePage(pageToMerge);
			}
		}
	}
}

A possible workaround is to use the RadFixedDocument`s Merge() method: 

document1.Merge(document2);