buttonBorderThickness: Number

Sets the border thickness of buttons (zoom/pan, reset & export-menu) in chart toolbar.

• Border will not be added if there is only one button in the toolbar.

var chart= new CanvasJS.Chart("container",
{
 .
 .
 toolbar: {
     buttonBorderThickness: 2,
     .
     .
 },
 .
 . 
});
chart.render();