The following description has been added for AbstractButton.setMnemonic(int)
in JDK1.4 doc.
However, if the mnemonic is not found in the label, the mnemonic isn't
displayed. This should be implemented properly.

> If the character defined by the mnemonic is found within
> the button's label string, the first occurrence of it will
> be underlined to indicate the mnemonic to the user. If the
> corresponding character is not contained within the button's
> label, then it will be displayed near the label in a look
> and feel dependent manner (commonly to the right, surrounded
> by parenthesis).