Hi Emanuele,
Thank you for using Syncfusion products.
We were unable to reproduce the reported issue "Pressing "+" button spins value from 0 to 100 instead of 1" in SfNumericUpDown control. We have prepared a sample and video to demonstrate the replication steps followed from our side, you can download it from the following link:
Sample:
NumericUpDown_SpinToMaxVideo:
VideoSfNumericUpDown value may spin from 0 to 100 directly on single press only if StepValue property is set to 100. Please check the value of StepValue property from your side and get back to us with modified sample reproducing the issue so that we can proceed further on this.
Regards,
Jessie