The same property is available for MS TooltipService in WPF. 

Implement a mechanism that allows embedding font data when exporting documents.

ApplicationMenu do not have keyboard navigation - pressing arrows do not navigate thru the application menu items.
Declined as a duplicate of: https://feedback.telerik.com/wpf/1352753-ribbonview-applicationmenu-do-not-have-keyboard-navigation.

Add support for axis with multi-level categories
Declined as a duplicate of: https://feedback.telerik.com/wpf/1351027-chartview-add-support-for-axis-with-multi-level-categories

You could repair the invalid file using the project from the attachment.

This will allow import of Tensor-product patch mesh gradients.

 

At the moment GIF images are not supported in SL RadRichTextBox

Users want to be able to resize columns of RadPivotGrid at runtime, similar to RadGridView.

This feature is available with our latest official version - R1 2019.

The regular ComboBox goes through all of the starting with the same letter items when pressing the same key multiple times. RadComboBox currently always highlights the first one.
In addition, the case where starting to type couple letters, will select the matched item with StartsWith

Allow users to expand properties of a complex type in order to reveal the list of that type's properties.

The feature will be available in R1 2019, scheduled for the mid of January 2019. 

JavaScript actions causes a script to be compiled and executed by the JavaScript interpreter. Depending on the nature of the script, the values of the interactive form fields in the document can be validated or updated or the visual appearances of the fields can be changed.

At this point the Ctrl + Insert shortcut doesn't work, while the Shift + Insert is pasting the text in the editor, but the pasted text is not visible until you start to type. 

This item is declined because it is wrongly logged and the issue is duplicated with another feedback item. You may follow instead these feedback item which also provides a sample attached project for repairing such invalid files:

https://feedback.telerik.com/Project/143/Feedback/Details/170586-pdfviewer-handle-documents-containing-invalid-cross-reference-table-start-index

For now, the static methods of ExtensibilityManager class are the only option to extend all RadPdfViewer instances.

Due to Silverlight limitations, currently only the user can specify which pages to be printed. We will consider implementing this custom functionality.

This item is declined because there are many PDF annotation types and we are going to create separate items for each type. You may follow some of the existing annotation feedback items listed below or create a new one which the Telerik team is going to approve. Here follows the list of the existing feedback items:
https://feedback.telerik.com/Project/143/Feedback/Details/167439-pdfviewer-support-for-annotations-of-type-stamp
https://feedback.telerik.com/Project/143/Feedback/Details/203379-pdfviewer-support-for-annotations-of-type-popup
https://feedback.telerik.com/Project/143/Feedback/Details/199351-pdfviewer-support-for-freetext-annotation-type
https://feedback.telerik.com/Project/143/Feedback/Details/149974-pdfviewer-highlight-annotation

Silverlight will be end of life in 2021. But if you look at at the currently supported browsers https://en.wikipedia.org/wiki/Microsoft_Silverlight#Desktop_computers you will see it is only running on Internet Explorer 11. All other browsers have canceled support for Silverlight.

Does it really makes sense to still support Silverlight?

I'm asking because of this: https://docs.telerik.com/devtools/wpf/xamlflix-step-by-step-guide/xamlflix-radbarcode. This is the WPF documentation for radBarcode but it effectivly is talking about Silverlight!