Hi fleetfoot, from the https://moi3d.com main web site, go to "Resources" (https://moi3d.com/resources) and in there find the link for "Max Smirnov's MoI scripts" (https://moi3d.com/wiki/MaxScriptArchive).

On Max's script archive page it's at the top: CustomUI.2.0.beta2.zip (https://moi3d.com/download/scripts/max/CustomUI.2.0.beta2.zip)

- Michael