Hello Seth Lowrey,
Browsers are trimming any additional spaces and this causes the unexpected behavior - check out the page source for the generated html in the Web Report Viewer. The HTML Rendering engine doesn't trim spaces and you can verify this in the generated HTML. Generally Tab character is a control character not a printable character. Check out the HTML ASCII Reference.
However if you want to add a printable meaning to the tab control character you can replace it with a printable character of your choice with an User Function as shown in the following code snippet. Up to the new line behavior you have experienced we have suspicions that your issue is that you have used carriage return (chr(13)) as a new line - can you try using Environment.NewLine or vbCrLf instead and let us know of the outcome?
public static object replaceTab(string value)
return value.Replace("\t", " ").Replace(" ", " ​").Replace("\r",Environment.NewLine);
All the best,
the Telerik team