Archiving all tasks in a folded project concatenates the next project to the first

[kschutter]

If I start with:

Project 1:
  ✔ Completed Item
Project 2:
  ☐ 2's task

And fold Project 1 to get this:

Project 1: [...]
Project 2:
  ☐ 2's task

Archiving will erroneously produce this:

Project 1: [...]Project 2:
  ☐ 2's task

When it should be:

Project 1:
Project 2:
  ☐ 2's task