Allow to password-protect a workbook, so that it cannot be shown (read) without the password.

Add APIs for creating and manipulating Chart objects.

Exported protected document containing be opened even if the correct password is used. The same behavior is reproduced with document(without pages).

Implement functionality to support scenario when a document which already has a signature to be signed again or add two or more signatures.

Currently, Telerik Document Processing is available only for .NET Framework and (partially) for Silverlight. Create version targeting .NET Core.

Update: There is a version of Telerik Document Processing compatible with .NET Core 3.0 in the UI for WPF suite. You can use this version in .NET Core projects running on Windows. The assemblies can be downloaded from telerik.com, the Downloads section of UI for WPF -> Betas tab. Please, note that you should have a valid license for UI for WPF in order to be able to see this version. In case you don't, you can use the Trial license by downloading a trial version of the suite. More information about this version of UI for WPF and how it can be used is available in the related blog post.

Currently, signature flags, represented by the 'SigFlags' optional entry, are not imported and exported, and there is no API for setting them.
As a result, documents signed with RadPdfProcessing (or with RadPdfViewer) appear in Adobe Reader without the blue document message bar at the top (the analogue of the RadPdfViewer's SignaturePanel).

If the API is supported, setting the flag to 1 or 3 would ensure that the message bar would be visualized in Adobe Reader.

This element specifies the settings for the document grid, which enables precise layout of full-width East Asian language characters within a document by specifying the desired number of characters per line and lines per page for all East Asian text content in this section.

Support conversion of XPS documents to PDF using RadPdfProcessing.

Add support for setting and exporting document metadata, like Title, Author and similar.

Provide a way to export filters.

At this point, CsvWorkbookExporter flushes the data to the underlying stream each time a new data is added. This leads to decreased performance. Ensure the best possible performance by flushing the stream at the end of the content generation.

Provide a way to change the Name of a FormField from the RadDocument.AcroForm.FormFields collection.

As a workaround, you could create a new instance of a FormField with the desired name, add the new field in the document and remove the old one. You can use the following approach:
   1) Create a new instance of FormField (with the desired name, passed in the constructor), which will play the role of a copy of a specific FormField
   2) Copy all properties from the original field (they all vary, depending on the concrete type of the FormField, for example CheckBoxField, etc.)
   3) Create a new widget for the new field, and copy all properties from the original field's widget into the new one.
   4) Remove the original field from the RadDocument.AcroForm.FormFields collection and add the new field.
   5) Remove the original widget from the corresponding page's annotation and add the new one.

Attached is a project demonstrating this approach for a CheckBoxField.

Although it is mandatory according to the specification, It seems like other applications don't require this record. Trying to open such an archive with RadZipLibrary currently throws InvalidDataException. 7zip creates such files.

They are exported with the /EmbeddedFiles switch. This would allow adding external files to the PDF document.

At this point the PdfFormatProvider does not support floating images and these elements are skipped when exporting to PDF.

The feature is trivial for floating images with "Behind Text"/"In Front of Text" settings, but otherwise floating images are affecting the text layout in complex ways.

When a HTML has a wrong encoding set (content="text/html; charset=utf-16") we use the UTF-16 encoding when importing this HTML. This leads to wrong import. 
Microsoft Word detects that the set encoding is wrong and uses UTF-8 instead so that the imported result is correct. 

The HTML5 specification forbids the use of the meta element to declare UTF-16, because the values must be ASCII-compatible: https://www.w3.org/International/questions/qa-html-encoding-declarations#utf16 

Provide the ability to work with images in headers/footers of a worksheet. Note that large images put in headers are visualized as watermarks on printing/exporting to PDF.

The CropBox is currently not supported by RadFixedPage class and is not preserved on an Import-Export scenario with PdfFormatProvider. CropBox is also not supported by PdfPageSource class and it is not preserved by using PdfStreamWriter as well. This property should be implemented in both scenarios.

Provide ability for working with comments in a spreadsheet document.