I'd like to create a custom thickness editor that works in a similar way to your colour editor. For example, in your PropertyGrid Integration (Custom) demo you have Fill and Stroke properties that display the colour and value as the property value and then, when the drop-down is activated, display a custom colour editor. In my case I'd like to put a custom thickness editor in the drop-down and then display the current thickness value in the property value using the normal thickness format. For example Margin 1cm,1cm,1cm,1cm. Can you advise how I can achieve a similar look-and-feel to your colour editor?