tdf#122238 KDE5: disable mechanism of Qt for shortcut activation

When QEvent::KeyPress event is processed, QEvent::ShortcutOverride event is created
and processed before finishing processing original event.

If it's an active shortcut, and QEvent::ShortcutOverride event is not accepted,
the shortcut is activated, but QEvent::KeyPress event is omitted.
If it's an active shortcut, and QEvent::ShortcutOverride event is accepted,
the shortcut is not activated, and QEvent::KeyPress event is sent as usual.

But it looks like even if shortcut activation is suppressed,
shortcut is still called somewhere from insides SalEvent::KeyInput
event processing callback from Qt5Widget::handleKeyEvent function.

Shortcuts are still assigned to menu actions
since it shows the key combinations used to activate them.

Change-Id: I1ffc63c2530dd61ae67ab66a96ea3efe767218c0
Reviewed-on: https://gerrit.libreoffice.org/66444
Tested-by: Jenkins
Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>
diff --git a/vcl/inc/qt5/Qt5Widget.hxx b/vcl/inc/qt5/Qt5Widget.hxx
index 26f26c8..4337792 100644
--- a/vcl/inc/qt5/Qt5Widget.hxx
+++ b/vcl/inc/qt5/Qt5Widget.hxx
@@ -45,6 +45,8 @@ class Qt5Widget : public QWidget
    bool handleKeyEvent(QKeyEvent*, bool);
    void handleMouseButtonEvent(QMouseEvent*, bool);

    virtual bool event(QEvent*) override;

    virtual void focusInEvent(QFocusEvent*) override;
    virtual void focusOutEvent(QFocusEvent*) override;
    virtual void keyPressEvent(QKeyEvent*) override;
diff --git a/vcl/qt5/Qt5Widget.cxx b/vcl/qt5/Qt5Widget.cxx
index e96a1b1..6d75cd60 100644
--- a/vcl/qt5/Qt5Widget.cxx
+++ b/vcl/qt5/Qt5Widget.cxx
@@ -395,6 +395,22 @@ bool Qt5Widget::handleKeyEvent(QKeyEvent* pEvent, bool bDown)
    return bStopProcessingKey;
}

bool Qt5Widget::event(QEvent* pEvent)
{
    if (pEvent->type() == QEvent::ShortcutOverride)
    {
        // Accepted event disables shortcut activation,
        // but enables keypress event.
        // If event is not accepted and shortcut is successfully activated,
        // KeyPress event is omitted.
        // It looks like handleKeyEvent function still activates the shortcut on KeyPress event,
        // so there's no harm in disabling shortcut activation via Qt mechanisms.
        pEvent->accept();
    }

    return QWidget::event(pEvent);
}

void Qt5Widget::keyPressEvent(QKeyEvent* pEvent)
{
    if (handleKeyEvent(pEvent, true))