Highchart: Line at bottom-border appear

Question

I made a highchart and now have a problem. When I zoom, the YAxis-Gridline is out of the border and the border-bottom-line is thicker than before. Is there a option, which I configured wrong or why does this Line on the bottom appear and the gridline is over the border? I tried to set lineWidth: 0, but didnt change anything

See this jsfiddle: jsfiddle After a zoom the problem appear.

Answer 1

It is known bug, which is reported here