An implementation of JPXDecoder should be created to allow the decompression of data encoded using the wavelet-based JPEG2000 standard.

Guidelines of how to provide a custom implementation of the JPXDecode filter can be found in the Customize Rendering section of the documentation and a sample implementation can be found in the SDK examples.

By specification, the InteractiveForm fields can have the same name if they are descendants of a common ancestor. Such fields are different representations of the same underlying field; they should differ only in properties that specify their visual appearance. When such a document is imported an ArgumentException: 'An item with the same key has already been added.' is thrown, which leads to non-editable fields in RadPdfViewer.

When the FixedDocumentSinglePagePresenter content control is used to visualize PDF files in custom PDF viewer implementation a raise condition can be occurred leading to NullReferenceException with the following stack trace:
at Telerik.Windows.Documents.Fixed.UI.UIElementsHelper.FillPageContentElementsInPanel(Canvas container, RadFixedPage page)
at Telerik.Windows.Documents.UI.FixedDocumentSinglePagePresenter.CreateContent(RadFixedPage page)
at Telerik.Windows.Documents.UI.FixedDocumentSinglePagePresenter.PageLoader_WorkCompleted(Object sender, WorkCompletedEventArgs e)
at Telerik.Windows.Documents.Utilities.ResourceLoader.OnWorkCompleted(WorkCompletedEventArgs args)
at Telerik.Windows.Documents.Utilities.ResourceLoader.Worker_RunWorkerCompleted(Object sender, RunWorkerCompletedEventArgs e)
at System.ComponentModel.BackgroundWorker.OnRunWorkerCompleted(RunWorkerCompletedEventArgs e)
at System.ComponentModel.BackgroundWorker.AsyncOperationCompleted(Object arg)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)

The exception is thrown since the current page is unloaded while the content is being parsed.

The EI keyword defines an operator for ending the image data. When the stream contains the same sequence, the parser treats that as an end of the image data. As a result, the image and the following content cannot be properly parsed and there is missing content when the document is visualized.

The offset of the CropBox is not respected and is always treated as 0.

Workaround: Import the document with PdfProcessing, change the CropBox offsets of the pages to 0, export the modified document and then import it in PdfViewer.

They are used by the page and the XObjects drawn on it and deal with the overlaying of the colors. These groups are described on page 556 of PdfReference 1.7. 

Telerik.Windows.Zip.InvalidDataException for unknown (0xAD) compression method is thrown for some object streams.

RadPdfViewer does not read image resources defined in Form XObject elements.

Implement import of documents containing Type 3 fonts.

This happens only in scenarios when the widget has On state appearance defined and Off state appearance missing. If both appearances are missing then RadPdfViewer recalculates the appearances and the checkbox is successfully selected and deselected.

I want to draw the signature box, like in Adobe Acrobat Reader.

This is very important when the document needs more than 1 signature.

Add PrintPreview dialog visualizing the way the document is going to be printed.

Add support for interactive forms based on the Adobe XML Forms Architecture (XFA). XFA specifies an XFA resource, which is an XML stream that contains the information of the form. The format of an XFA resource is described in the XML Data Package (XDP) Specification. The XFA resource provides most of the information about the form; in particular, all form-related events such as calculations and validations.

We should implement the logic for getting character codes from Unicode when using CFFFontSource.
Workaround: The font may be changed by creating a similar font with FontsRepository.TryCreateFont(...) method.

In the PDF document model, the Annotation appearances refer to an external resource using the Resources dictionary. When the Resources dictionary is defined as an Indirect Object an InvalidCastException: 'Unable to cast object of type 'Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Types.PdfDictionary' to type 'Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.DocumentStructure.PdfResource'.', is thrown.

Workaround for documents generated with PdfProcessing: When drawing lines using the FixedContentEditor the IsFilled graphic property should be set to false:

RadFixedDocument document = new RadFixedDocument();

Rect rect = new Rect(0, 0, 50, 50);
FixedContentEditor editor = new FixedContentEditor(document.Pages.AddPage());
editor.GraphicProperties.IsFilled = false;
editor.GraphicProperties.IsStroked = true;

editor.Position.Translate(50, 50);
editor.GraphicProperties.StrokeColor = new RgbColor(255, 0, 0);
editor.DrawText("Lines");
editor.DrawLine(rect.TopLeft, rect.TopRight);
editor.DrawLine(rect.TopRight, rect.BottomRight);
editor.DrawLine(rect.BottomRight, rect.BottomLeft);
editor.DrawLine(rect.BottomLeft, rect.TopLeft);

The widgets of the interactive forms are not respected when creating a thumbnail from a PDF page. Implement logic for adding the form fields widgets to the generated image as well.

This is reproducible for images with FlateDecode and predictor value in the range between 10 and 15. As an example you may take a look at the DecodeParms property in the following image PDF dictionary:

<< /BitsPerComponent 8 /ColorSpace /DeviceRGB /DecodeParms << /BitsPerComponent 8 /Colors 3 /Columns 1024 /Predictor 15 >> /Filter /FlateDecode /Height 2868 /Subtype /Image /Type /XObject /Width 1024 /Length 1236707 >>

When importing document containing a destination which points to invalid page reference, KeyNotFoundException is thrown.

Dialog for inputting the password should be implemented in order to be able to decrypt the file content.