Comment 2 for bug 211768

Confirmed. The same thing can also be seen at a larger scale by sending an e-mail--as the block rolls across the progress bar for action-with-unknown-progress, the block starts with its right end at the left end of the progress bar:
=====(...................................................................)
instead of what it should be:
          (=====.........................................................)

And the ripply-effect background is erased as the block rolls over it, leaving a plain grey band across the centre of the progress bar.

Attached is a screenshot showing both problems.