jControls NF4 also requires specific project settings to work properly. The project should be upgraded to an SDK-style project, and it should be configured for 64-bit platforms, as 32-bit platforms are not supported. A reference to the ComfileTech.jControlsNF4 library needs to be added, and the program's main form needs to inherit from jForm in order to host jControls.

To avoid the hassle of upgrading an ordinary .NET Framework 4 WinForms project, configuring it properly, and creating and configuring the main form, save yourself the trouble, and always use one of the jControls Visual Studio project templates. When using one of the jControls Visual Studio project templates, you'll always have a working project with a jForm ready to go, so you can immediately begin adding controls to build your solution.