How to use this balloon styling:
Instead of this:
The second style is activated when I set following option:
"chartCursor": {
"cursorPosition": "mouse"
}
The second styling is the so called drop. It is activated by a setting in the respective balloon configuration (located in the graph settings):
"balloon":{
"drop":true
}
To deactivate the drop you can either set it to false or just delete it (default is false).