Hi there,
This is my day one to Nevron. I am just trying to begin to use Community version, for now, to see how people will like it. 

I follow http://helpdotnetvision.nevron.com/Activation.html steps added 3 .Net Community Edition licenses to the Nervron License Manager, however, the watermark is still there in the WPF app.

Is that community version always comes with the watermark or did I do something wrong? 

Hi Gen,
First, thank you for your interest in Nevron Chart for .NET.
Please take a look at the following page:
https://www.nevron.com/orders-dot-net-chart-community-edition.aspx
it lists the license keys you can use to unlock the Lite edition of the control. We just tested with the following code:

NLicenseManager.Instance.SetLicense(new NLicense("00003c56-efbb-b1b6-0300-01a33008598d, 073c7566-4c00-2a00-5102-57006a01f915"));

and it successfully unlocks the control in both design and redistribution mode. 
We hope this helps - let us know if you meet any problems or have any questions.

Best Regards,
Nevron Support Team