Gradient lines are not rendered if all y-axis values are the same

[jnncks]

Codepen

https://codepen.io/anon/pen/RdWVoj

Explanation

• What is the behavior you expect?

  If all y-axis values of a series are the same and a gradient is used for the fill of a line chart, the line is being rendered properly.

• What is happening instead?

  The line is not being rendered at all.
  Also, the ticks of the y-axis all have the same value if no min or max value has been set.

• What error message are you getting?

  None.