Log: Fine-tuning related to new icons.

The main motivation was to avoid element header title showing when
mouse hovers between new icons and to avoid accidentally triggering
element toggle if click misses the icons slightly. This required few
separate changes:

- HTML was changed so that only the left header has a title and the
  right header overrides it with "".

- HTML was changed so that the right header stops all click
  propagation. This also removed lot of duplication when individual
  icons/buttons don't need to stop clicks.

- Styles were changed so that the main header has no padding that
  could accidentally be clicked in the right end. Padding was moved to
  left and right headers instead. Related paddings and margins were
  cleaned up in general as a result.