this is something I notices about 6 months ago. Don't know if it was a
regression or I had never noticed it before.
If I select a zoom area with the mouse, the top , bottom and right hand
coords are used but it does not always seem to catch the left hand one.
I think this is happening if there are several plot lines.
I have a plot with six lines showing this oddity but one with four that
I have had a college report the same thing on windoze builds.
If that does not make sense I'll try to narrow it down a bit more.