Hi Riad,
Thanks for contacting Syncfusion support.
We have checked your query but we are unable to reproduce the reported issue. We have configured the CurrencyTextBox control as you have mentioned in your update but the application works properly .We have attached simple sample reflecting the same.
Can you please provide details, like stack trace when application crashes, and system/application local culture. Can you modify the samples to reproduce the issue, if it does not match with reported query? It will be helpful for us to proceed further.
Note: Negative sign entered before zero value will be removed as zero cannot have negative value.
Regards,
Niranjan Kumar Gopalan