Hello A K,
The DestroyOnClose property will not work in this case as you expect - please try with and without it to confirm that the behavior will be the same. This property works only when the navigate url is used and this is the case in which it makes sense.
If you need to clear some values you can directly do this on the server or on the client because the controls reside in the very same page when ContentTemplate is used. If you continue experiencing problems, please send a very simple fully runnable page code here (no need for wizard, you can replicate e.g with a textbox) along with very detailed reproduction steps and explanations of the exact actual and desired behavior and differences between them and I will help you achieve what you need.
the Telerik team
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