Unable to enter negative value to Numeric Mask Currency

Hi, Mujaqo,

NumberFormatInfo.CurrencyNegativePattern property sets the format pattern for negative currency values. Note that the default for InvariantInfo is 0, which represents "($n)". Please refer to the following article for more information: https://docs.microsoft.com/en-us/dotnet/api/system.globalization.numberformatinfo.currencynegativepattern?view=netcore-3.1.

It seems that on your machine is the default value, this is why you see the negative values with "()". In order to change this setting, you can do it through your local Region settings. In the Negative currency format filed you can choose from the drop-down the appropriate pattern that you would like to use. Below is a picture for your reference:

Another way is to set it programmatically via the CultureInfo class.

This is the result on my end:     
   

I hope this information helps. Do not hesitate to contact us if you have other questions.

Regards,
Nadya
Progress Telerik