Automatic or easy to configure support for displaying the UAC shield icon when the command that will be executed by the Button or the Menu item will require elevated permissions.

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

File explorer with the drag and drop upload and just a richer interface

The control should be more customized than normal status bar control for WPF.

The XAML team has recently reviewed this issue and will not be addressing it as with Q1 2014 we introduced theme support for the System.Windows.StatusBar component. This means that you can use the native component within a Telerik powered application and at the same time have a seamless look and feel.  

You can check our Theming SDK demo under MSControls by downloading our SDK browser for WPF on the following page: http://demos.telerik.com/xaml-sdkbrowser/

If you want to share additional requirements about this control please contact us through the support ticketing system with details and a reference to this item.

Coming from RadControls for WinForms I did miss this control.
It didn't take me long to create my own alert controls, but it would be nicer to have them styled and behave like all other telerik controls.

Add: ListView Control

A control that allows you to generate complex layouts.

Available since R3 2016 Official Release.

Add a new Captcha control

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

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.

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.

Develop  a new control - Reflection Control.

Features to support:
- Text blocks with basic formatting, preferably draggable, and preferably with customizable borders/backgrounds.
- Basic drawing functionality such as pencil, brush, lines, circles, rectangles etc. Of course with color selection for lines and fill. 
- Line thickness selection. 
- Being able to move the objects around the board would be nice.
- Connecting objects with some sort of connector lines, pretty much like the map structure in SketchFlow, if you are familiar with that. 
- Some basic shapes, such as arrows and icons that can be dragged/dropped on to the board.
- Support for uploading images and dragging them onto the stage. 
- XAML export (necessary for saving a drawing)
- Printing
- Magic marker/highlight functionality
- Collaboration support. This is a big one, and I am not sure how it should be implemented. Full collaboration functionality out of the box would require a service running duplex WCF or something similar. Alternatively, perhaps Telerik could provide us customers with an API and some sample code. Then we could handle the back-end stuff ourselves.

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Our XAML team has recently reviewed the status of this feature request. Since most of this requirements are covered by our RadDiagram Control / Framework we are changing the status to Completed.
Please follow RadDiagram documentation:
http://docs.telerik.com/devtools/wpf/controls/raddiagram/overview.html

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/

Create a contour plot control for Silverlight. http://mathworld.wolfram.com/ContourPlot.html

Develop Apple/MAC theme

Create a Button editor control