Thank you for writing.
Please make sure that you have added an Aqua
theme instance to your form and that you have the Telerik.WinControls.Themes.Aqua
assembly referenced. You can do it with drag and drop the toolbox in the designer in Visual Studio. Please check the following section of our documentation: Themes
I hope this helps. Should you have further questions please do not hesitate to write back.
Check out the Windows Forms project converter, which aids the conversion process from standard Windows Forms applications written in C# or VB to Telerik UI for WinForms.For more information check out this blog post
and share your thoughts.