Hi there!

I'm using a XamNumericEditor to edit a decimal property on my ViewModel. The ValueType is set to System.Decimal. While debugging from visual studio, the control is extremely unresponsive. I investigated using profiling tools and such and discovered that the control was causing a lot of exceptions to be thrown. I disabled the "Just my Code" setting and enabled managed breakpoints and discovered that this exception is thrown nearly constantly (10-15 times per keystroke):

System.FormatException occurred
  Message=Input string was not in a correct format.
  Source=mscorlib
  StackTrace:
       at System.Number.ParseDouble(String value, NumberStyles options, NumberFormatInfo numfmt)
   Infragistics3.Wpf.Editors.v10.1.dll!Infragistics.Windows.Editors.FractionPart.GetFractionValue() + 0x13b bytes   
     Infragistics3.Wpf.Editors.v10.1.dll!Infragistics.Windows.Editors.FractionPart.CanSpin(bool up = true) + 0x52 bytes   
     Infragistics3.Wpf.Editors.v10.1.dll!Infragistics.Windows.Editors.EditInfo.CanSpin(bool up = true, object amount) + 0x130 bytes   
     Infragistics3.Wpf.Editors.v10.1.dll!Infragistics.Windows.Editors.EditInfo.CurrentState.get() + 0x396 bytes

It performs much better outside of the debugger which probably explains why it was missed during testing (assuming you tested the scenario :-)).