Thanks for writing.
I am afraid that there is little we can do inside the conversation view to change that. All applications behave like this. If you really have to fix this you can find the text box inside RadConversationView and listen for its GotFocus and LostFocus events. Then you can apply a render transform on the conversation view to move it down. This is a hack however and should not be included inside the control itself.
Please have a look at the attached sample app. It demonstrates the exact same behavior with a simple TextBox.
Thank you for understanding.
the Telerik team