GH: Preview Material doesn't update

So when I modify a material in Rhino, and if I reference that material in a Custom Preview component, the modified material doesn’t update/propagate to the Viewport when I close the material dialog.

WA: Only when I disconnect the material name (panel text) from the Custom Preview and then reconnect it, only then the updated material is updated also in the viewport.

Fig.1.: Only when disconnecting and reconnecting again, the modified material is updated also in the Viewport

// Rolf