This type of destinations is not supported and leads to InvalidCastException when importing such elements.

This is reproducible with specific PDF files which use custom Encoding for the fonts of the field widgets. 

WORKAROUND: Change the font of VariableContentWidgets before editing the field value. You should additionally call RecalculateContent() method of these widgets if the value of their corresponding fields is not edited. The following method may be used for changing the font of all existing widgets in the document:

private static void FixEncodingIssues(RadFixedDocument document)
{
    foreach(Annotation annotation in document.Annotations)
    {
        VariableContentWidget widget = annotation as VariableContentWidget;

        if(widget != null)
        {
            widget.TextProperties.Font = FontsRepository.Helvetica;
        }
    }
}

Add support for ToUnicode CMap stream.

A side effect of not supporting it is the following: exporting PDF document which, for example, contains German umlauts, to plain text, leads to wrong characters in the resulting text.

As possible workaround, the PdfFormatProvider instance of RadPdfViewer can be used to import the document. For example:

FormatProviderSettings settings = new FormatProviderSettings(ReadingMode.OnDemand);
PdfFormatProvider pdfViewerFormatProvider = new PdfFormatProvider(stream, settings);
 
RadFixedDocument document = pdfViewerFormatProvider.Import();
 
TextFormatProvider textFormatProvider = new TextFormatProvider();
String text = textFormatProvider.Export(document);

The construct <link rel="stylesheet" href="main.min.css" /> doesn't raise the HtmlImportSettings.LoadFromUri event on import, as we currently require type="text\css" to be specified explicitly.

Although Lab color space is currently unsupported, the provider should not throw exceptions that break the whole file import.

Implement API for adding document outline (a.k.a bookmarks).

When the document contains an image that is defined as an external resource but is not available in the specified location and cannot be found, a KeyNotFoundException is thrown. Handle this exception and replace the missing image with a default one for such cases. Consider exposing an option to notify the user about this error.

When the imported html contains an attribute of the type width="", Wordsprocessing throws ArgumentException and does not import the document. 

Importing an image from HTML with URI as a source, which has applied only width or height and exporting it to PDF (which forces getting the image data so it can be drawn) leads to an incorrect value of 1 (a default value) for the dimension that is not specified.

When the document contains an image with extension, which is not among the supported ones, a KeyNotFoundException is thrown during Import.

An ArgumentException is thrown when importing HTML containing standard and non-standard pseudo classes or pseudo elements. The concreete scenario is the following: 
.myclass::-webkit-scrollbar or .myclass::-ms-expand

The message of the exception is similar to this: "Unexpected character found at position [X]: ".. scrollbar::>>-<<webkit-scrollbar"". 

When there is long text that is out of the used cell range area, this text should be included in page splitting calculations.

Also, when a cell has text that overflows its width, the text is again clipped by the cell boundaries and is not visible in the exported PDF. In a similar case Excel exports the surrounding cells to ensure that the content is visible.

Workaround: Extend the used cell range to include all the cells which the text content spans.