The unresolved count on a file header opened the whole thread list scrolled to that file, which covered the code in
a narrow view and did not tell the file's threads apart. Each click now goes to the file's next unresolved thread in
the order its section shows them: threads on the whole file, threads on lines by the row of their last line,
outdated threads, then threads the chosen commits do not hold; after the last it starts again from the first. The
thread list orders each file's threads the same way, and the Threads toolbar button alone opens it.