Hi Luca,
Please elaborate on the problem - as mentioned above the control can automatically scale the labels sizes if it encounters one of the above conditions - you can switch off both using:
Hope this helps - let us know if you meet any problems...
Best Regards,Nevron Support Team
The font size can change due to one of the following reasons:
1. The axis uses automatic auto scaling to resolve overlapping labels.
2. The axis zone bounds exceed the maximum specified zone bounds (by default 30 percent of the plot area).
Can you send us a screenshot of the chart you're having problems with for review?