Cannot see _ (underscore) in WPF content

Question

A very simple question:

Why I cant see _ (underscore) in WPF content?

For instance the content of

Answer 1

Labels support mnemonics (i.e. you can use ctrl+(key) to give them focus). You define the mnemonic key using an underscore.

http://www.charlespetzold.com/blog/2006/01/061004.html

If you want to see underscores, replace single underscores with double underscores.