http://www.telerik.com/community/forums/silverlight/general-discussions/feature-request-callout-control.aspx

Add a new Captcha control

A new Tag Cloud control similar to the WinForms and ASP.NET Ajax counterparts (http://demos.telerik.com/aspnet-ajax/tagcloud/examples/overview/defaultcs.aspx)

New control request: FishEye menu.

NEW Kanban Control

LIKE 
https://www.devexpress.com/Subscriptions/New-2016-2.xml#winforms
https://www.syncfusion.com/products/wpf/sfkanban

I'd like to put in my request to have a control that would allow to magnify a part of the image as mouse goes over. Here is link to see a running sample:
http://www.fordracingparts.com/parts/part_details.asp?PartKeyField=11439
As you move your mouse over, another window opens up to show a magnified version.

An advanced search textbox control for WPF. A good example can be found at: http://davidowens.wordpress.com/2009/02/18/wpf-search-text-box/

Currently the palette of a theme can only be set for the entire application. Setting the palette per control instance should also be possible.

New Control: WPF Web Browser

Develop  a new control - Fisheye Panel.

It would be very helpful if you can plan to create kind of a "drawing tool" to design specific views for flows, state models, workflows, etc.

Similar to File Explorer in Windows 10, it would be helpful to have a Quick Access section in the left navigation pane with the ability to pin frequently used items.

There is an open source library (http://bitmiracle.com/libtiff) that can be used to convert the TIFF images to different formats and then visualize the resultant file with an appropriate control (e.g. convert the TIFF to PDF document and import it in RadPdfViewer).

Create NuGet symbol packages - containing the .pdb files - corresponding to the primary NuGet packages. The process is described here: https://docs.microsoft.com/en-us/nuget/create-packages/symbol-packages .

This will facilitate the debugging of problems in the controls code.

Introduce control similar to TextBox which offers integrated spell-checking (similar to the one provided in RadRichTextBox).

Develop  a new control - Reflection Control.

Something like an image Viewer for WPF with some kind of animation, not too fancy though.