De Por que o Ctrl + Alt não deve ser usado como um modificador de atalho :
You may have noticed that Windows doesn't use Ctrl+Alt as a keyboard shortcut anywhere. (Or at least it shouldn't.) If a chorded modifier is needed, it's usually Ctrl+Shift.
That's because Ctrl+Alt has special meaning on many keyboards. The combination Ctrl+Alt is also known as AltGr, and it acts as an alternate shift key.
Most international keyboards remap the right-hand Alt key to act as AltGr, so instead of the finger-contorting Ctrl+Alt+Q, you can usually type RAlt+Q.
Sometimes a program accidentally uses Ctrl+Alt as a shortcut modifier and they get bug reports like, "Every time I type the letter 'đ', the program thinks I want to start a mailmerge."