How to add PowerPoint's ShapeFill Button to a custom Ribbon in a C# PowerPoint AddIn?

I am developing a PowerPoint AddIn using C#. In PowerPoint's default ribbon, the ShapeFill button is implemented as a split button—where the left side functions as a regular button, and the right side is a gallery of colors for filling shapes.

I would like to replicate this functionality in my custom ribbon, but I am not sure how to properly implement a split button with this type of behavior. Specifically, I need the left button to trigger an action and the right gallery to display color options for filling shapes.

Is there a way to directly reuse PowerPoint's built-in ShapeFill button in a custom ribbon, or will I need to recreate the split button and gallery functionality manually? Any guidance or examples would be appreciated.

https://learn.microsoft.com/en-us/openspecs/office_standards/ms-customui/f2a8e3c0-14cb-4ad3-88cd-a8b5b1b9a8a0

Microsoft says the 'ShapeFillColorPicker' is a gallery. I currently have this code in my Ribbon.xml but the button is not the same as the PowerPoint built-in one.

<gallery idMso="ShapeFillColorPicker" showLabel="false" size="normal" supertip="Select color for shape"/>
<gallery idMso="ShapeOutlineColorPicker" showLabel="false" size="normal" supertip="Select color for shape outline"/>
<gallery idMso="TextFillColorPicker" showLabel="false" size="normal" supertip="Select color for text"/>