When Windows11Theme is applied before the PdfViewer is initialized the CurrentPageTextBox is not loaded successfully.

Workaround: Set the ApplicationTheme after the InitializeComponent method:

 

When specific culture is set (e.g. Hebrew but not only) in a project targeting .NET 5 (or later), some documents are not rendered correctly (rendered as blank pages).

The width height of the tilling drawing is not converted correctly which leads to exception

Path geometries with a small thickness value are not displayed correctly 

Some images with SMask applied are not rendered in the viewer.

When the page is rotated the Stamp annotation is not rendered correctly:

From the PDF Specification: "An ink annotation represents a freehand “scribble” composed of one or more disjoint paths. When opened, it displays a pop-up window containing the text of the associated note."

Sometimes the Ink annotations are imported as UnsupportedAnnotation and not displayed as expected. In such cases, the annotations could be removed from the RadFixedPage content in the following manner:

From the PDF specification: "The current stroking alpha constant, specifying the constant shape or constant opacity value to be used for stroking operations in the transparent imaging model."

VS 2022 designer exception when PdfViewer is dragged and dropped from the toolbox.

From PDF Specification: "The value of the field dictionary’s Ff entry is an unsigned 32-bit integer containing flags specifying various characteristics of the field. Bit positions within the flag word are numbered from 1 (low-order) to 32 (high-order)."

Field flags common to all field types: ReadOnly, Required, NoExport.

The Field textbox is too large when the field height is limited and the text is not visible when one is typing.

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

An invalid certificate is not imported correctly and causes exception on export. We should be able to handle this and skip the import without breaking the file. 

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.

Implement editor functionalities like add, edit or delete content.

When rendering PDF file with a TrueType font and Unicode platform Id (platformId: 0), glyphs are not obtained from CMAP table and are displayed with default rectangle placeholders.

Scanned document is not rendered with the new engine

This type of dictionary allows users to specify files and define different files for different systems or platforms.

The image quality is poor when rendering large images.

The leak is reproducible when printing documents without UI and results in multiple instances of DocumentPrintPresenter kept alive in the memory.