The functionality provided by GUIKit has been superseded by the interface construction and controls functions native to the built-in Wolfram Language.
GUIKit Example: ColorChooser
Code
Definition
Example
This example uses Widget["ColorChooser"] and includes sample code demonstrating how to do the following.
Bind a Wolfram Language script to execute each time the selected color changes.
Create a custom color well whose background color changes with the selection.
Add a modal result binding so a Wolfram Language color primitive is returned to the kernel when the dialog session ends.
Define a utility wrapper function around the GUIRunModal call, demonstrating a single reusable instance of the dialog used throughout the lifetime of the kernel session.