plot: wrong glyphbox for non-centered axes labels

[sbinet]

The glyphbox for axes labels that aren't centered (the default position), isn't correctly computed:

[kortschak]

When did that happen? I thought this used to work.

Oh, these are right-aligned, right? Is there code for this?

[sbinet]

Yes, right-aligned or top-aligned.
There isn't yet code that tests for this with drawing the glyphbox.
(I think the glyphbox is correctly computed, just incorrectly drawn)