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Details

Type: Bug
Resolution: Fixed
Priority: P1: Critical
Fix Version/s: 6.4.3, 6.5.0, 6.6.0
Affects Version/s: 6.4.0
Component/s: GUI: Basic Input System (keyboard, mouse, touch)
Labels:
None

Platform/s:

macOS
Commits:
0835537c3 (dev), 091160a9a (6.5), 598022cdc (6.4)

Description

If an action with Cmd+Return shortcut is present in the main application menu, then an event with type QEvent::ShortcutOverride is not invoked when this shortcut is pressed. The problem seems to be on macOS only, the corresponding Ctrl+Return works well on Windows and Linux. The problem curiously does not exist if the action is not present in the main menu or is disabled. This problem also does not exist for many other 'innocent' shortcuts such as Cmd+R, Cmd+I, etc.

The consequence of this problem is that you cannot override the application-wide Cmd+Return shortcut and handle this shortcut locally in a widget by handling its corresponding key press event.

The following code is to illustrate the problem. There are two global shortcuts but each of them behaves different. I try to block these global shortcuts by setting shortcut override event as accepted in the event filter and then processing the key press event locally. But blocking of Cmd+Return does not work because QEvent::ShortcutOverride event is not issue at all.

#include <QAction>
#include <QApplication>
#include <QDebug>
#include <QKeyEvent>
#include <QMainWindow>
#include <QMenu>
#include <QMenuBar>
#include <QTextEdit>

class MainWindow : public QMainWindow
{
public:
    MainWindow(QWidget *parent = nullptr) : QMainWindow(parent)
    {
        auto menu = new QMenu("Menu");
        auto menuBar = new QMenuBar();
        menuBar->addMenu(menu);
        setMenuBar(menuBar);

        auto action1 = new QAction("Action 1");
        action1->setShortcut({Qt::CTRL | Qt::Key_Return}); // evil "unblockable" shortcut
        menu->addAction(action1);
        connect(action1, &QAction::triggered, this, []{ qDebug() << "action 1"; } );

        auto action2 = new QAction("Action 2");
        action2->setShortcut({Qt::CTRL | Qt::Key_R}); // innocent "blockable" shortcut
        menu->addAction(action2);
        connect(action2, &QAction::triggered, this, []{ qDebug() << "action 2"; } );

        auto textEdit = new QTextEdit();
        setCentralWidget(textEdit);
        textEdit->installEventFilter(this);
    }

protected:
    bool eventFilter(QObject *watched, QEvent *event) override
    {
        if (event->type() == QEvent::ShortcutOverride)
        {
            // setting as accepted blocks the global shortcut
            auto keyEvent = static_cast<QKeyEvent*>(event);
            qDebug() << "shortcut override" << keyEvent;
            event->setAccepted(true); 
            return true;
        }

        if (event->type() == QEvent::KeyPress)
        {
            // this is the local key shortcut handler
            auto keyEvent = static_cast<QKeyEvent*>(event);
            qDebug() << "key press" << keyEvent;
            return true;
        }

        return false;
    }
};

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    return a.exec();
}