allow global keyboard shortcuts in all widgets by default

Master filters events in all widgets. For key press events, it is
checked whether the widget handles the event itself. If not, Master
handles it.

src/gui/thumbnailbutton.cpp

@@ -27,7 +27,7 @@ void ThumbnailButton::mouseReleaseEvent(QMouseEvent *event)
 
 void ThumbnailButton::focusInEvent(QFocusEvent*)
 {
-    setFrameStyle(QFrame::Panel);
+    setFrameStyle(QFrame::Panel | QFrame::Plain);
     setLineWidth(2);
     QPalette palette;
     palette.setColor(QPalette::WindowText, Qt::red);

src/master.cpp

@@ -475,7 +475,6 @@ QWidget* Master::createWidget(QJsonObject &object, QWidget *parent)
         // Mute slides by default, except if they are marked as master.
         if (!object.value("mute").toBool(!object.value("master").toBool(false)))
             scene->flags() &= ~SlideScene::MuteSlide;
-        connect(slide, &SlideView::sendKeyEvent, this, &Master::receiveKeyEvent);
         connect(slide, &SlideView::sendAction, this, &Master::handleAction);
         connect(scene, &SlideScene::navigationToViews, slide, &SlideView::pageChanged, Qt::DirectConnection);
         widget = slide;
@@ -605,6 +604,7 @@ QWidget* Master::createWidget(QJsonObject &object, QWidget *parent)
     }
     if (widget)
     {
+        widget->installEventFilter(this);
         // Add keyboard shortcut.
         if (object.contains("keys"))
         {
@@ -641,17 +641,24 @@ void Master::showAll() const
     }
 }
 
-void Master::receiveKeyEvent(const QKeyEvent* event)
+bool Master::eventFilter(QObject *obj, QEvent *event)
 {
+    if (event->type() != QEvent::KeyPress)
+        return QObject::eventFilter(obj, event);
+    event->ignore();
+    obj->event(event);
+    if (event->isAccepted())
+        return true;
+    const auto *kevent = static_cast<QKeyEvent*>(event);
 #if (QT_VERSION_MAJOR >= 6)
-    const QKeySequence key_code(event->keyCombination());
+    const QKeySequence key_code(kevent->keyCombination());
 #else
-    const quint32 key_code = event->key() | (event->modifiers() & ~Qt::KeypadModifier);
+    const quint32 key_code = kevent->key() | (kevent->modifiers() & ~Qt::KeypadModifier);
 #endif
     // Search shortcuts for given key sequence.
     {
         QWidget* widget = shortcuts.value(key_code);
-        debug_msg(DebugKeyInput, "Key action:" << widget << event << (event->key() | (event->modifiers() & ~Qt::KeypadModifier)));
+        debug_msg(DebugKeyInput, "Key action:" << widget << kevent << (kevent->key() | (kevent->modifiers() & ~Qt::KeypadModifier)));
         if (widget)
         {
             widget->show();
@@ -692,6 +699,8 @@ void Master::receiveKeyEvent(const QKeyEvent* event)
                 setTool(new Tool(*tool));
         }
     }
+    event->accept();
+    return true;
 }
 
 void Master::nextSlide() const noexcept

src/master.h

@@ -99,11 +99,11 @@ class Master : public QObject
     /// Get open file name from QFileDialog
     static QString getOpenFileName();
 
-public slots:
-    /// Handle key events collected by any other object.
-    /// By default all key events are redirected to this and handled here.
-    void receiveKeyEvent(const QKeyEvent* event);
+protected:
+    /// Filter key input events from other widgets
+    bool eventFilter(QObject *obj, QEvent *event) override;
 
+public slots:
     /// Read memory size restriction from preferences and distribute memory to pixcaches.
     void distributeMemory();