Allow partial uploads

[jidanni]

Description

Just like in MarcusWolschon/osmeditor4android#2573 , it would be great in iD if we could choose which items we want to upload now, and which we want to work a little more on first!

Screenshots

No response

[matkoniecz]

that is adding horrible amount of complexity without strong reason

[tyrasd]

While, I personally would have liked to have such a feature on some occasions, it would be quite hard to make an intuitive UI/UX for this, and the effort would not outweigh the benefits of having it. My workaround is to open a secondary iD session in another browser tabs in order to work on a separate changeset while having partial edits kept "parked" in the first browser tab.