When creating UI texts, do not use casing to indicate functionality or meaning. The reason for this is that most non-Latin writing systems do not have the concept of casing at all, and the languages that do use uppercase and lowercase use them in different ways.
For example:
In some languages, there is not a one–to–one mapping between the uppercase and the lowercase character. For example, the German lowercase 'ß' is 'SS' in uppercase.
Languages can have different mappings between uppercase and lowercase. For example, in English, the lowercase 'i' maps to a different uppercase character than it does in Turkish.
Use the Qt folding methods QString::toUpper() and QString::toLower() to convert characters from lowercase to uppercase, and vice versa.