The existing User Control list can be extended to provide additional controls.
Implementation
Paste your User Control into your plugin solution.
Make your plugin implement IUBIKEnvironmentControl and add the export.
[Export(typeof(IUBIKControl))] public partial class CtrlAtelierHost : UserControl, IUBIKEnvironmentControl
The user control now has a property Description and Image.
The text of description and the image will show up in the User Control List.
After making the changes make sure to update the plugin in the injection folder.
Extended user control list
Window
A new button can be added to the UI and open the injected UI