Importing document with invalid bookmarks throws System.Collections.Generic.KeyNotFoundException. The issue is caused by an invalid bookmark having missing BookmarkRangeStart/bookmarkStart or BookmarkRangeEnd/bookmarkEnd elements.

When exporting, an option of how to create the PDF bookmarks should be provided:
- Using the RadFlowDocument bookmarks
- Using document Headings

The non-breaking hyphen element is currently not supported in the model and is stripped when importing the document.

The calculations are wrong, leading to single lines on a page. As a result, the content of the PDF document is laid out on a bigger number of pages.

Workaround: Change the line spacing and its type before exporting to PDF:

foreach (var paragraph in this.document.EnumerateChildrenOfType<Paragraph>())
{
	HeightType? heightType = paragraph.Properties.LineSpacingType.GetActualValue();
	if (heightType == HeightType.Exact || heightType == HeightType.AtLeast) 
	{
		paragraph.Properties.LineSpacingType.LocalValue = Telerik.Windows.Documents.Flow.Model.Styles.HeightType.Auto;
		paragraph.Properties.LineSpacing.LocalValue = 2;
	}
}