title: Missing values on second y-axis
body: <p>I want to plot 3 sets of y-values, where I want to have values for "Temperature" shown on one Y-axis, and both "Total Energy" and "Potential Energy" values shown on the other y-axis.
  My plotting command is:</p>
  
  <pre><code>plot "traj_read.out" using 3:7 title 'Temperature' w lines, \
  "traj_read.out" using 3:4 axes x1y2 title 'Total Energy' w lines, \
  "traj_read.out" using 3:6 axes x1y2 title 'Potential Energy' w lines
  </code></pre>
  
  <p>The lines are displayed well, but only the values for "Temperatures" are shown on the Y-axis to the left, values on the right y-axis are missing.</p>
  
  <p>Hope someone has a tip how to scale those axes!</p>