Available in the 2015 Q3 SP.
Available in LIB 2016.3.919 and also it would be available in 2016 R3 SP1.
The issue is fixed through the UpdateValueToMatchTextOnLostFocus dependency property, introduced in the 2015 Q2 SP1 release.
Available in LIB version 2016.1.302, it will be also available in the 2016 Q2 Release.
As a workaround you can change the NumberNegativePattern to the default one like so: System.Globalization.CultureInfo ci = (System.Globalization.CultureInfo)System.Threading.Thread.CurrentThread.CurrentCulture.Clone(); ci.NumberFormat.NumberNegativePattern = 1; Thread.CurrentThread.CurrentCulture = ci; Thread.CurrentThread.CurrentUICulture = ci;