the regular - next to 0 works on my RadMaskedTextInput, but the one on the number pad doesn't.  Here is my style I'm using:
    <Style x:Key="UpperCodes6Mask" TargetType="telerik:RadMaskedTextInput">
        <Setter Property="FontFamily" Value="Segoe UI" />
        <Setter Property="Margin" Value="0 0 0 0" />
        <Setter Property="Width" Value="60" />
        <Setter Property="Height" Value="20" />
        <Setter Property="Padding" Value="0" />
        <Setter Property="Placeholder" Value=" " />
        <Setter Property="IsClearButtonVisible" Value="False" />
        <Setter Property="TextMode" Value="PlainText" />
        <Setter Property="SectionsNavigationMode" Value="None" />
        <Setter Property="IsLastPositionEditable" Value="False" />
        <Setter Property="SelectionOnFocus" Value="SelectAll" />
        <Setter Property="Mask" Value=">a6" />
    </Style>

Hi Dan,

The minus sign on the NumPad isn't considered as a valid input in a MaskedTextInput control, while the dash key is considered as a valid input in a Mask="aaa". However, you can customize your MaskedTextInput to add a dash in its value when the Substract key is hit by handling the RadMaskedTextInput KedDown event:

Please give this a try and let me know if it works for you.

Kind regards,
Tina Stancheva
the Telerik team

Well why does, '/' , '*' and '+' work on the number pad but not '-'?  That doesn't really make sense.

Also the above code always puts the - at the end.  If I put the cursor in the middle of some text and hit - it will just append the text.

Hi Dan,

Thank you for getting back to us. I can see your point on the matter and this is why I logged a new task (making the Substract key a valid input in a MaskedTextInput) in our PITS. You can both vote to increase the priority of the task and track its progress through this link.

As for my workaround, it adds the "-" at the end as I have implemented a logic that simply extends the value of the control((sender as RadMaskedTextInput).Value += "-"). But you can customize this approach to insert the "-" at the current caret position. Let me know if you have any troubles implementing such an approach.

Kind regards,
Tina Stancheva
the Telerik team

Apparently this issue got lost in the mix and the PITS link is dead. I've created a new ticket in the new feedback portal though to follow up on this issue.

Hello Jeff,

Thank you for using our Feedback portal to submit the bug report. I approved it as it was already logged in our PITS system.

Please follow the submitted item and stay tuned for any changes.

Regards,
Pavel R. Pavlov
Telerik