RadMaskedNumericInput ValidationTooltip empty text

[Yuri]

Hello,
I use

<telerik:RadMaskedNumericInput x:Name="tbNumberOfPeriods" Grid.Row="1" Grid.Column="3" Width="40"
             Value="{Binding Path=CustomCalendar.NumberOfPeriods, Mode=TwoWay, ElementName=customCalendarControl, UpdateSourceTrigger=PropertyChanged, NotifyOnValidationError=True, ValidatesOnExceptions=True}"
             ErrorMessage="{Binding Path=Text, ElementName=customErrorMessage}"
              AutoFillNumberGroupSeparators="False" TextMode="MaskedText" Mask="#2.0" IsClearButtonVisible="False" AutoFillZeros="False"
              TabIndex="2" IsLastPositionEditable="False" />

when first time i clicked on the validation error I got empty text in ValidationTooltip. Error text becomes normal when I lost focus from browser(alt+tab or Ctrl+Esc or again clicked validation error).
ValidationTooltip and RadMaskedNumericInput have default styles.
Telerik.Windows.Controls version: 2013.1.403.1050
Any ideas how to fix it?

[Petar Mladenov]

Hello Yuri,

Could you please send us your ViewModel's code ? You can check out our help articles for validation:
Throwing Validation Exception
Using DataAnnotation Attributes
Please have in mind that there are some differences in the two approaches. For example, the second one needs setting AllowInvalidValues to True. Let us know if using one of these cause the mentioned issue too.

Regards,
Petar Mladenov
Telerik