In Microsoft Windows menus, labels, and other captions, the ampersand is used to denote the next letter as a keyboard shortcut (called an "Access key" by Microsoft). For instance setting a button label to makes it display as rint and for to be a shortcut equivalent to pressing that button. A double ampersand is needed in order to display a real ampersand. This convention originated in the first WIN32 api, and is used in Windows Forms, (but not WPF, which uses underscore for this purpose) and is also copied into many other toolkits on multiple operating systems. Sometimes this causes problems similar to other programs that fail to sanitize markup from user input, for instance Navision databases have trouble if this character in either "Text" or "Code" fields.