Thank you for the question.
You are correct. If you call RadComboBox.Focus() in Form_Shown or at a later moment of the application cycle, you should be able to focus the textbox portion of the RadComboBox. However, currently we have an issue with this behavior. It will be addressed in one of our next versions.
For the time being, in Q3 2008 SP1 it is enough to call RadComboBox.Select() which will focus the textbox portion.
However, if you are using an older version of RadControls, please consider using the following code snippet:
If you have additional questions, feel free to contact me.
the Telerik team
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