When displaying PDF-Files using PDFViewer, ContentElementsCanvas .RenderAsync uses reflection (DispatcherObjectUtils.ApplyDispatcher) to render Visuals on multiple threads.
However this leads to a memory leak since the dispatchers cant be GC'ed, see screenshot below.




The Screenshot is from the actual application we expirienced this issue with, the attached reproduction example is a boiled down version of what your code does.
If you wanna reproduce this on your own, create an application that uses PdfViewer that switches between many pdf files. The ammount of Dispatchers will grow steadily, probably to a total of the number of threads used by Task.Factory.

COMException: 'Exception from HRESULT: 0x8052000C' breaks the printing of the a specific document.

The text elements in a document are positioned wrongly and are slightly offset from their expected positions.

The ColorSpace element is not required for images which are using JPXDecode filter.

Zooming changes the current page number in continuous view.

GoToPage() method is not working correctly in some cases when called in DocumentChanged event handler. The known cases are described below:

   1. When RadPdfViewer and the document are loaded initially and document is set through the RadPdfViewer.Document property.
Workaround: DocumentSource property could be set (in XAML or in code-behind) instead of the Document property. If the Document property is used, this should be done after RadPdfViewer is loaded.

    2. When the ScaleMode is changed in DocumentChanged event handler and then GoToPage() method is called in the same event handler.

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.

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

Tint transformation function is used to transform Device N color in Alternate colorspace.

Observed when loading a document: 

Text selection in RadPdfViewer exhibits precision issues where mouse-based selection struggles to accurately capture desired text boundaries. Selection frequently overshoots or undershoots the intended range, and copied text may contain duplicated content or unexpected spacing artifacts.

PDF Signature(image) is displayed on the incorrect location when using annotations.

Some of the lines that should be dashed are rendered as continuous lines.

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 PdfViewer has slow performance when rendering images that have large size but are scaled down.

There are missing characters when importing documents containing Standard fonts with a Differences array defined in the Encoding, which contains characters that do not fit in the first 255 glyph definitions in the font. Most of these characters are the ones with an accent such as "ccaron" (č).

The slow performance when creating thumbnail is only reproducible with specific documents.

As a result, the glyphs are not measured and positioned properly. The issue applies to the TrueType and Type1 fonts.

The PDF document with images shows black canvas:

NOTE:

Works OK in version 2023.2.713
Broken in version 2023.3.1005

Images hosted inside multiple Form XObjects are not rendered.