With the current implementation, the optional Filter property is omitted on export.

According to PDF specification, the field value should be specified in the "V" entry of the corresponding PDF dictionary. However, some PDF producers are skipping this entry and are setting only the Widgets appearance states. As most viewers manage to show the radio button and checkbox as selected, we should handle this scenario and import the field values based on the related widgets when this value is not explicitly set with the field's V entry.

IndexOutOfRangeException thrown when executing CalculateMultidimensionalLinearInterpolationResult method of SampledFunction class.

Invalid position when the TJ operator array contains empty values (<>).

Exporting a field with missing Appearances property causes exception

Signature widgets are not imported correctly.

When using the PdfStreamWriter to write a PdfPageSource whose content has "Predictor 1" set as DecodeParms an error message is shown when opening the exported document with Adobe reader.

InvalidCastException when importing link annotations that are referenced with indirect reference. 

For some documents, the clippings and colors of the geometries are modified on an import-export scenario.

When the bookmarks are declared as objects instead of a string they are not visible.

Exception when the endstream is no on a new row 

By specification, FitH destinations are defined with page and top position. A null value for top specifies that the current value of that parameter is to be retained unchanged. However, importing such a document with PdfProcessing leads to ArgumentOutOfRangeException:  'Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index'.

The appearance dictionary specifies how the annotation is presented visually on the page. If the appearance missing or is empty in PDF document NullReferenceException is thrown on import. 

Reading Type1 font glyph data when there is a table with differences tries to get the glyph by name but it is not found. 

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

Workaround: Change the LineSpacingType to HeightType.Auto.

The Helvetica-UltraCompressed font is not parsed correctly and is changed to Helvetica. 

Export of a document with Type 1 font and custom encoding results in content loss.

IOException when an object in the cross-reference stream has a negative offset.

"System.IO.IOException: An attempt was made to move the file pointer before the beginning of the file."

The PdfFormatProvider currently supports such an option (check the ImageCompression setting).

When a document is exported with a cross-reference stream, the stream is missing the required according to the specification Length property. Although most of the viewers open the document without any issues, some cannot. Such documents cannot be opened in MS Edge.