QLineEdit vs ApplicationShortcut

[Kryzon]

To answer my own question, if you reimplement the "bool event( QEvent* event )" handler, you can catch QEvent::ShortcutOverride events that represent shortcut sequences that you want to interpret differently in the widget.

Using this solved the problem:

bool CustomLineEdit::event( QEvent* event )
{
	switch( event->type() )
	{
	case QEvent::ShortcutOverride:
		event->accept();
		return true;
		break;
 
	default: // Important to avoid compiler warnings about unhandled QEvent types.
		return QLineEdit::event( event );
		break;
	}
}

bool CustomLineEdit::event( QEvent* event )
{
	switch( event->type() )
	{
	case QEvent::ShortcutOverride:
		event->accept();
		return true;
		break;

	default: // Important to avoid compiler warnings about unhandled QEvent types.
		return QLineEdit::event( event );
		break;
	}
}

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Now the widget accepts "x" as text input when it has keyboard focus, and when it doesn't the QAction is invoked instead.
More information here: http://wiki.qt.io/ShortcutOverride