When IsEditable is set to true the SelectedItem is not updated if you delete the SelectedItem's text to match another existing item.

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"

When the app is in full screen OOB mode the placement of the drop down portion of the ComboBox control is incorrect.

The issue can be reproduced also with the standard ComboBox:
https://connect.microsoft.com/VisualStudio/feedback/details/663870/wpf-4-0-combobox-itemtemplate-and-selectionboxitemtemplate-when-itemtemplate-is-bound#details

Workaround: use OnDropDownClosed event.

RadComboBox and RadRibbonComboBox in their NonEditable mode do not reflect background set inline. A style for the ToggleButton contained in the NonEditable templates prevents the TemplateBinding from working properly as it uses a hard-coded background. For RadRibbonComboBox it is a Metro theme-only issue.

IsEditable=True and ReadOnly=True

Steps to Create Problem using  EditableTextBoxTemplate_WPF sample project provided by Telerik:(modified project is zipped and attached just in case)

- Edit Example.xaml to add "AllowMultipleSelection="True":

            <telerik:RadComboBox  IsEditable="True" ItemsSource="{Binding Companies}" SelectAllTextEvent="None" FontFamily="Calibri" FontSize="14"
                                  DisplayMemberPath="Name" EditableTemplate="{StaticResource EditableComboBox}"
                                  Width="220" Height="50" DropDownWidth="*" x:Name="comboBox" Margin="5 10" AllowMultipleSelection="True"/>
        </StackPanel>

 

1) Run project 

2) Click drop down button to see list in the drop down

3) Type "Global" (at this point it should autocomplete "Global Corporation")

4) Without clicking on anything or Press space bar to continue typing (type space character)

5) Typed text will disappear leaving only space character behind - At this point, nothing is selected.

 

This does NOT happen if typed text before space does NOT match with any item from the list. 

This does NOT happen if AllowMultipleSelection set to false. 

This does NOT happen if dropdown is NOT open while typing.

 

RadComboBox with IsEditable = true, IsReadOnly = true and IsFilteringEnabled = true. Select an item and then in order for the filtering to work you have to delete the selected text with Backspace

See the supported thread.

When using similar code as below, RadComboBox does not select the specified item. If the DomainDataSource data was already loaded, the selection is successful.
<telerikInput:RadComboBox ItemsSource="{Binding ElementName=MineTypeDomainDataSource, Path=Data}"
  SelectedItem="{Binding Path=MineType, Mode=TwoWay, NotifyOnValidationError=true, ValidatesOnExceptions=true}"> 
 <telerikInput:RadComboBox.ItemTemplate> 
  <DataTemplate> 
   <TextBlock Text="{Binding MineTypeName}" HorizontalAlignment="Left" /> 
  </DataTemplate> 
 </telerikInput:RadComboBox.ItemTemplate>  
</telerikInput:RadComboBox>  
<riaControls:DomainDataSource AutoLoad="True"
  x:Name="MineTypeDomainDataSource"
  QueryName="GetMineTypesQuery"
  LoadedData="MineTypeDomainDataSource_LoadedData"
  DomainContext="{StaticResource CitationDBSvc}" />

Specifically this bug was found in WPF, I'm not sure of its state in Silverlight.
The FontWeight is permanently some shade of Bold when using Metro.
This is demonstrated in the Telerik WPF demos in the ComboBox/Theming demo.

After making a selection in the control and changing the theme two times in a row an InvalidOperationException is thrown about the animation.

Currently, there is an internal API that determines whether partial matches can be selected or not. Provide public options to change this behavior. By default partial matches are selected.

In the meantime, the default behavior can be changed using reflection to set the CanAutocompleteSelectPartialMatches property of RadComboBox to False.