First of all, let me provide some information about the NumericTextBox HTML output and how it works:
In short, you have a <div> for the formatted value, which is positioned over an <input> with the unformatted value.
As you have seen in the help article above, when the NumericTextBox is blurred, the textbox content is hidden. However, Internet Explorer does not allow changing the text color of disabled elements or removing the text shadow. Hiding the text inside the textbox with negative text-indent style seems impossible (in IE). That's why we apply large letter-spacing style to the textbox, so that its content is hidden as much as possible and the formatted value is left visible. Unfortunately, when using letter-spacing, the first number in the textbox remains visible and this causes the shadow that you are seeing.
With regard to right alignment, please refer to a forum thread of yours on the same topic:
All the best,
the Telerik team
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