Make it possible to assign shortcut to multitrack view

Fixes #229

src/kdenliveui.rc

 <!DOCTYPE kpartgui SYSTEM "kpartgui.dtd">
-<kpartgui name="kdenlive" version="160" translationDomain="kdenlive">
+<kpartgui name="kdenlive" version="161" translationDomain="kdenlive">
   <MenuBar>
     <Menu name="file" >
       <Action name="dvd_wizard" />
@@ -182,6 +182,7 @@
       <Action name="mark_out" />
       <Separator />
       <Action name="monitor_fullscreen" />
+      <Action name="monitor_multitrack" />
       <Action name="monitor_zoomin" />
       <Action name="monitor_zoomout" />
       <Menu name="monitor_config_overlay" ><text>Current Monitor Overlay</text>

src/monitor/monitor.cpp

@@ -136,7 +136,6 @@ Monitor::Monitor(Kdenlive::MonitorId id, MonitorManager *manager, QWidget *paren
     , m_recManager(nullptr)
     , m_loopClipAction(nullptr)
     , m_sceneVisibilityAction(nullptr)
-    , m_multitrackView(nullptr)
     , m_contextMenu(nullptr)
     , m_markerMenu(nullptr)
     , m_loopClipTransition(true)
@@ -490,10 +489,7 @@ void Monitor::setupMenu(QMenu *goMenu, QMenu *overlayMenu, QAction *playZone, QA
     m_contextMenu->addAction(m_monitorManager->getAction(QStringLiteral("extract_frame_to_project")));
 
     if (m_id == Kdenlive::ProjectMonitor) {
-        m_multitrackView =
-            m_contextMenu->addAction(QIcon::fromTheme(QStringLiteral("view-split-left-right")), i18n("Multitrack view"), this, SIGNAL(multitrackView(bool)));
-        m_multitrackView->setCheckable(true);
-        m_configMenu->addAction(m_multitrackView);
+        m_contextMenu->addAction(m_monitorManager->getAction(QStringLiteral("monitor_multitrack")));
     } else if (m_id == Kdenlive::ClipMonitor) {
         QAction *setThumbFrame =
             m_contextMenu->addAction(QIcon::fromTheme(QStringLiteral("document-new")), i18n("Set current image as thumbnail"), this, SLOT(slotSetThumbFrame()));
@@ -1447,9 +1443,6 @@ void Monitor::setCustomProfile(const QString &profile, const Timecode &tc)
     }
     slotActivateMonitor();
     // render->prepareProfileReset(tc.fps());
-    if (m_multitrackView) {
-        m_multitrackView->setChecked(false);
-    }
     // TODO: this is a temporary profile for DVD preview, it should not alter project profile
     // pCore->setCurrentProfile(profile);
     m_glMonitor->reloadProfile();

src/monitor/monitor.h

@@ -208,7 +208,6 @@ private:
     QAction *m_loopClipAction;
     QAction *m_sceneVisibilityAction;
     QAction *m_zoomVisibilityAction;
-    QAction *m_multitrackView;
     QMenu *m_contextMenu;
     QMenu *m_configMenu;
     QMenu *m_playMenu;

src/monitor/monitormanager.cpp

@@ -407,6 +407,15 @@ void MonitorManager::setupActions()
     connect(projectStart, &QAction::triggered, this, &MonitorManager::slotStart);
     pCore->window()->addAction(QStringLiteral("seek_start"), projectStart, Qt::CTRL + Qt::Key_Home);
 
+    QAction *multiTrack = new QAction(QIcon::fromTheme(QStringLiteral("view-split-left-right")), i18n("Multitrack view"), this);
+    multiTrack->setCheckable(true);
+    connect(multiTrack, &QAction::triggered, [&](bool checked) {
+        if (m_projectMonitor) {
+            m_projectMonitor->multitrackView(checked);
+        }
+    });
+    pCore->window()->addAction(QStringLiteral("monitor_multitrack"), multiTrack);
+
     QAction *projectEnd = new QAction(QIcon::fromTheme(QStringLiteral("go-last")), i18n("Go to Project End"), this);
     connect(projectEnd, &QAction::triggered, this, &MonitorManager::slotEnd);
     pCore->window()->addAction(QStringLiteral("seek_end"), projectEnd, Qt::CTRL + Qt::Key_End);