Thank you for taking your time to guide me here. It’s always a pleasure for me to learn new tricks for JOSM. Is it correct, that your method only works for existing objects, not for deleted?

To learn from my mistakes, I need to relate the changes to the imagery used. I only know how to do this via Task Manager and taskID. That's the reason for my request.

Hello, thank you for validating. However, your remarks are useless, unless I can relate them to a specific task - as I have previously informed you

Thank you for providing the TaskId using a task comment (and yes, way/540137204 should definitely not be tagged as 'service')

But I should have checked with the Marathoner tool…
Thanks for validating

Yes, I do. In this case the only modes used were Draw buildings (B) and Extrude (X), so the 'non-squaredness' is a bit strange.
By the way: As I mentioned at your previous comment to another task: When you communicate in this way with changeset comments, please mention the relevant taskID. Alternatively, use Task comments.

Hmmm - yes, that's more or less what I did...
But thanks :)

Hello Frans S, thanks for your validations and for writing comments. I really appreciate it. I am aware of the principle of moving the outline of the roof area to the footprint of a tall building, as shown in the video. At least for nice, boxy buildings (although I can see from your corrections that I have overlooked some here). However, I am unsure how to handle some of the more complex buildings, where the lower parts may be hidden behind the higher parts of the building. Hence the addition of a Fixme tag. Any advice regarding the mapping principle in these cases would be very welcome.
By the way, referring to the changeset in your comment is very useful. If possible, including the task id would be a great help to get back to the imagery.
I’m not used to communicate in this way, but I hope that you will be made aware of my comment here