I’m not sure if this a bug or user error. But if I select an island that has similar islands and just want to stack islands of the selected shape, the result is all islands including those not similar to the one selected are stacked even if the selected only option is on. I’ve included a clip. Also, all the tutorial clips I’ve seen have the option to choose “Selected Mode”, but as you can see in my interface that doesn’t appear as an option.
Please provide information about which version of Blender and Zen UV you are using. Also, indicate the status of UV Sync Selection. Unfortunately, I was unable to reproduce the same behavior. You may see differences in the interface because the add-on is constantly changing, and it is not possible to rewrite all videos according to the latest changes. A little more information about the changes can be found here.
I’m using Blender 4.5.4 LTS, Zen UV 5.2.1, UVPackmaster 3.4.4 with sync selection on. I just tried again after selecting all the faces in the 3D Viewport with sync selection off, and the stack selected function kind of works but kind of doesn’t with regards to scale. In the last selection, the shapes and orientation are the same, but the sizes are different.
In UVPackmaster 3 it’s possible to align the while toggling “Adjust Scale”.
I still cannot reproduce any of your issues. Please send your scene and indicate the steps to reproduce this issue.