Looks like this double prime may be the official symbol but users are typing what's available on the keyboard. Means the double quote. I guess I will use double prime but create aliases to map input of double quotes or two single quotes.   Added my current test plugin here. So if some one likes to check it out.   How does it work:   Each NumericUpDown control which shows a tooltip with units can accept values together with the units as input. The first uni