Upload dialog still lists closed changesets after JOSM knows they've been closed
- Upload some data to changeset FOO
- Wait an hour
- Try to upload to it. The server says you can't
- Go to upload dialog, it's still listed there in the drop-down list for open changesets
- Refresh changesets from the server. Says you have no open ones, but it's still listed
JOSM should remove items from the list of open changesets as soon as it knows they've been closed.