Overlay Buttons
It is possible to create buttons that remain overlaid on top of the picker.
Setup
Within the Advanced Editor's Attribute Editor, navigate to the Shapes tab and locate the Shape section. Set the option to Space to Screen. The anchor attributes specify the docking corner where you want to position the button relative to its container. The canvas serves as a guide to assist with placement."
Note: Marking a shape as screen space does not affect stack evaluation. A screen space shape can be drawn behind a world space one and does not enforce an overlay.