It sounds like you want to create a custom color editor class that extends the existing ColorEditor class. To add a new tab with custom colors, you will need to override the ColorUI class, which is nested inside the original ColorEditor class.
To do this, you can create a new class that extends the ColorEditor class and overrides the ColorUI class. Here is an example of how you might do this:
public class CustomColorEditor : ColorEditor
protected override void ColorUI(Color value)
Once you have created your custom color editor class, you can use it in your WinForms application by setting the PropertyEditor property of your PropertyGrid control to your custom color editor class.
Here is an example of how you might do this:
CustomColorEditor customColorEditor = new CustomColorEditor();
propertyGrid.PropertyEditor = customColorEditor;
I hope this helps!