We've tried to reproduce the issue, but with no luck. However there are a couple of things that you can check in your application:
- Have you applied any additional style for RadComboBox (implicit style with TargetType=Telerik:RadComboBox)?
- Have you applied any additional style for RadComboBoxItem (implicit style with TargetType=Telerik:RadComboBoxItem)?
- Have you applied any additional style for TextBox (implicit style with TargetType=TextBox)?
Any of the above could cause the unexpected behavior - it looks like in your application there is additional style for RadComboBox, which is setting Foreground to Black. If you are referencing any additional dlls, the problem could be caused by them - maybe in some of them you will find the style.
Hope this helps.
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