Hi, Dave!

I did not try it. But studying the project I arrived to the following workflow. First each scene is set to a specific map. Therefore you have four scenes displayed with map A and four scenes displayed with map B. Those settings have to be made under "Scene Properties" of each scene. Now when setting the "Thumbnails values" under "List Values" of the thumbnails" "Properties" you will see that all scenes are checked, which means that all scenes will be displayed as thumbnails, but you will also notice that "Items Vary with Different Maps" is also checked. That has to be why when changing the maps the thumbnails change also. The A and B buttons are not linked to the thummbnails in a direct way, but thru the maps, which are linked having "Items Vary..." checked.

I hope this helps. Regards, Martin

Edit: TW4.0 allows us to have the thumbnails changed and linked to different movies if we want, by creating fake maps and not showing them. Creating maps as pop up windows but not have any button nor link that shows it. Thanks to your question I realized this work around.