The RadListBox has an attached property for mvvm binding of SelectedItems - https://docs.telerik.com/devtools/wpf/controls/radlistbox/features/selecteditemssource.

Please support SelectedItemsSource for RadComboxBox too.

If you set IsEnabled = false, in the RadComboBox then (in the Office 2016 theme) the entire box is faded, including the text. A suggestion in the forum was to set IsHitTestVisible to false, as well as IsTabStop. This works, but it means that the dropdown button still looks enabled. It would be nice if IsReadOnly did what I wanted, but it doesn't. 
Therefore, either a way to set the Visibility/Opacity of the dropdown button. Or alternatively, modify the theme(s) to make the text more visible when the box is IsEnabled is set to false, in the same way as the standard ComboBox. 
I'm aware that I can modify the template myself, but it'd be nicer if it was built in. 

Combobox with 2 items -- "Item1"   and "it": typing "it" selects the 1st item which is "Item1" and it should select the second one which is "it"

It might also be nice to take it one step further and give the option to choose the key that fires an update off

Currently the control scrolls by group.

This would provide the option to stop the auto scrolling when the last item is hovered.

Enable the ComboBox to open its DropDown in up as well as down direction

When "TextSearchMode" is set to "Contains", IsEditable="True" and IsReadOnly="True": it should be possible to select all or some of the text and by pressing delete or backspace the selected text should be removed.

Workaround: use OnDropDownClosed event.

Available in the 2016 R3 Release.

Please check our help article for more information: 
http://docs.telerik.com/devtools/wpf/controls/radcombobox/features/multiple-selection

Allow the developers to style the TextBox area of a editable RadComboBox - add icons, change the string, format the text etc.

The combobox lists in Windows 10 settings (see attached pictures) have an interesting behavior which could be integrated by Telerik combox controls. The behavior is as following: when the listbox is opened, it appears above the combobox control with the selected item highlighted. And the placement of the listbox can change if the first item is selected (displayed down direction) or the last item is selected (display up direction).

It's difficult to explain that with simple words, so I suggest to see attached pictures to understand my request.

The control should allow customizations in its filtering functionality, for example, the developers should be able let RadComboBox match "Á" when the user types "A".