Don't attempt activating a monitor if it is hidden.

CCBUG: 422849

src/mainwindow.cpp

@@ -902,16 +902,6 @@ void MainWindow::saveProperties(KConfigGroup &config)
     }
 }
 
-void MainWindow::readProperties(const KConfigGroup &config)
-{
-    // read properties here
-    KXmlGuiWindow::readProperties(config);
-    // TODO: fix session management
-    /*if (qApp->isSessionRestored()) {
-    pCore->projectManager()->openFile(QUrl::fromLocalFile(config.readEntry("kdenlive_lastUrl", QString())));
-    }*/
-}
-
 void MainWindow::saveNewToolbarConfig()
 {
     KXmlGuiWindow::saveNewToolbarConfig();

src/mainwindow.h

@@ -146,8 +146,6 @@ protected:
     /** @brief Saves the file and the window properties when saving the session. */
     void saveProperties(KConfigGroup &config) override;
 
-    /** @brief Restores the window and the file when a session is loaded. */
-    void readProperties(const KConfigGroup &config) override;
     void saveNewToolbarConfig() override;
 
 private:

src/monitor/monitormanager.cpp

@@ -153,6 +153,10 @@ bool MonitorManager::activateMonitor(Kdenlive::MonitorId name)
             if (!m_clipMonitor->monitorIsFullScreen()) {
                 m_clipMonitor->parentWidget()->raise();
             }
+            if (!m_clipMonitor->isVisible()) {
+                m_activeMonitor = m_projectMonitor;
+                return false;
+            }
             emit updateOverlayInfos(name, KdenliveSettings::displayClipMonitorInfo());
             m_projectMonitor->displayAudioMonitor(false);
             m_clipMonitor->displayAudioMonitor(true);
@@ -160,6 +164,10 @@ bool MonitorManager::activateMonitor(Kdenlive::MonitorId name)
             if (!m_projectMonitor->monitorIsFullScreen()) {
                 m_projectMonitor->parentWidget()->raise();
             }
+            if (!m_projectMonitor->isVisible()) {
+                m_activeMonitor = m_clipMonitor;
+                return false;
+            }
             emit updateOverlayInfos(name, KdenliveSettings::displayProjectMonitorInfo());
             m_clipMonitor->displayAudioMonitor(false);
             m_projectMonitor->displayAudioMonitor(true);