Normal key shortcuts like copy, paste, cut, undo, etc. are broken by recent Qt updates. This happens in OS X when using a foreign input method.
Steps to reporduce:
1. Start using "2-Set Korean" IME.
2. Open "Find Files Dialog" demo from qtdemos
3. Type something into the "Named" box.
4. Try to undo, cut, paste, or copy with Command-Z, Command-X, Command-Z, or Command-C
Typing undone, selection cut, copied, or pasted.
This only happens when the key combinations are used. Right clicking and selecting one of the desired actions works as expected.