Hi. I'm seeing a recently-introduced issue with 'steps' plots. I'm using a dev build from https://github.com/gnuplot/gnuplot/commit/48960ad8545c68a908c168195dfff505d6b8dc5 ). Here's a small gnuplot script to demonstrate the issue:
set terminal x11
set ytics format "%7.3f"
set xrange [ 66696.6 : 66730.5 ]
set yrange [ 0.800000 : 2.20000 ]
plot '-' with steps
5307 1
5310 2
66715 1
66728 2
70203 1
e
This should produce a square-wave-like plot. However when zoomed-in with the given parameters, I get a plot that looks like the attached image. Note the missing horizontal line at the top-left. This horizontal line comes back when I zoom in or out a little bit. Resizing the plot window fixes it as well. To be clear many zoom/size combinations show the issue, but they are sparse. I did a bisection, and here's the commit that introduced the bug:
https://github.com/gnuplot/gnuplot/commit/9b53a591594df30447f121a1b1d4fa4312454418
