Hi Jean,
Thanks for using Syncfusion Products.
Could you please let me know what version of Essential Studio you are using?
I am not able to reproduce this issue which you have mentioned in the previous update[Version 5.1].
The following code snippet which illustrates how to invisible the Toolbar in chart control.
this.chartControl1.ShowToolbar = false;
(or)
this.chartControl1.ToolBar.Visible = false;
Please take a look at the attached sample.
http://websamples.syncfusion.com/samples/Chart.Windows/F14864/main.htmPlease let me know if this helps.
Regards,
Rashidha.