When importing the document as DocumentSource the stream will be loaded asynchronously and the document won't be loaded when the Print() method is called, NullReferenceException is thrown.

Use the attached project to reproduce. 

Workaround:

var combo = toolbar.ChildrenOfType<PercentComboBox>().FirstOrDefault();

var binding = new System.Windows.Data.Binding();
binding.Path = new System.Windows.PropertyPath("ScaleFactor");
binding.Mode = System.Windows.Data.BindingMode.TwoWay;
binding.Source = pdfViewer;
binding.UpdateSourceTrigger = System.Windows.Data.UpdateSourceTrigger.PropertyChanged;
BindingOperations.SetBinding(combo, PercentComboBox.ValueProperty, binding);

var binding1 = new System.Windows.Data.Binding();
binding1.Source = pdfViewer;
BindingOperations.SetBinding(combo, PercentComboBox.RadPdfViewerProperty, binding);

The stroke is not rendered when the text is in XForm

To reproduce:

- Search for a specific word until the last occurrence is found and a message appears. 

- Click the FindPrevious button

Result: A message appears.

Expected: The previous entry is selected. 

Whitespaces are ignored when copy-pasting from PdfViewer to another text redactor.

Document with invalid cross-reference stream is not loaded correctly

Unsupported annotations are rendered on top of other content. When there is a form field that appears inside the annotation, it cannot be clicked or interacted with as the annotation is capturing the mouse gestures.

WPF controls are used to visualize the form fields in PdfViewer. However, these controls inherit the background defined in the PdfViewer's theme instead of a background of the form field control. This leads to wrong visualization mostly in the dark themes as the content inside the form field might get unreadable.

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

Documents containing large images are slow to decompress and decode.

When RadPdfViewer is created on UI thread different than the Application main thread, an InvalidOperationException: 'The calling thread cannot access this object because a different thread owns it.' is thrown when calling the Copy method.

The character is visualized as '3'. The same issue is also reproducible when the content is copied from Adobe.

Loading document containing link with no destination leads to ArgumentNullException in PdfElementToFixedElementTranslator.CreateDestination method.

When importing a document with empty pages collection an ArgumentNullException: 'Value cannot be null.
Parameter name: page', is thrown, which leads to application crash.

Workaround: Import the document using the PdfProcessing library and add an empty page:

 

The CIDFont dictionary may contain an array, describing the widths of the glyphs. If the width has a negative value an ArgumentException: 'Width and Height must be non-negative.', is thrown when the document is imported in RadPdfViewer, which leads to application crash.

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.

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