Cmd+A (Select All) not working in native macOS file dialog

[for13to1]

Describe the bug

On macOS, pressing Cmd+A (Select All) in the native open file dialog has no effect. It is impossible to select all files using the keyboard shortcut.

To Reproduce

Steps to reproduce the behavior:

1. Run YUView on macOS.
2. Click the "Open" button on the left panel (or press Cmd+O) to show the native file dialog.
3. Try to press Cmd+A to select all files in the directory.
4. No files are selected.

Expected behavior

All files in the folder should be selected, matching the behavior on Windows (Ctrl+A).

Version

• OS: macOS
• Version: develop branch
• If you compiled YUView yourself then which Qt version did you use? Compiled with Qt 6.x

[for13to1]

https://forum.qt.io/topic/163117/macos-native-select-all-and-translations-cmd-a-behavior-vs-qtbase_xx.qm-shipping-of-qtbase_sv.qm-ts-qt-5.15.8

[for13to1]

https://stackoverflow.com/questions/32441273/enabling-the-qt-pyqt-qfiledialog-select-all-keyboard-shortcut-on-osx