restore add/remove dock buttons

--also use a single timer for screen sync
for dockview

app/dockcorona.cpp

@@ -267,11 +267,11 @@ void DockCorona::primaryOutputChanged()
         qDebug() << "Found screen: "<<scr->name();
     }
 
-    if (m_dockViews.count()==1 && qGuiApp->screens().size()==1) {
-        foreach(auto view, m_dockViews) {
-            view->setScreenToFollow(qGuiApp->primaryScreen());
-        }
-    }
+    //if (m_dockViews.count()==1 && qGuiApp->screens().size()==1) {
+      //  foreach(auto view, m_dockViews) {
+      //      view->setScreenToFollow(qGuiApp->primaryScreen());
+      //  }
+   // }
 }
 
 void DockCorona::screenRemoved(QScreen *screen)

app/dockview.cpp

@@ -93,6 +93,10 @@ DockView::DockView(Plasma::Corona *corona, QScreen *targetScreen)
         connect(dockCorona, &DockCorona::docksCountChanged, this, &DockView::docksCountChanged);
         connect(dockCorona, &DockCorona::dockLocationChanged, this, &DockView::dockLocationChanged);
     }
+
+    m_screenSyncTimer.setSingleShot(true);
+    m_screenSyncTimer.setInterval(3000);
+    connect(&m_screenSyncTimer, &QTimer::timeout, this, &DockView::reconsiderScreen);
 }
 
 DockView::~DockView()
@@ -226,7 +230,8 @@ void DockView::screenChanged(QScreen *scr)
    // }
 
   //  qDebug() << "Screen inconsistency!!! :" << scr->name() << " - " <<m_screenToFollow->name();
-    QTimer::singleShot(2500, this, &DockView::reconsiderScreen);
+    m_screenSyncTimer.start();
+    //QTimer::singleShot(2500, this, &DockView::reconsiderScreen);
 
     /*bool found{false};
     foreach(auto scr, qGuiApp->screens()){
@@ -477,7 +482,8 @@ inline void DockView::syncGeometry()
               //  found=true;
             }
         }
-        QTimer::singleShot(2500, this, &DockView::reconsiderScreen);
+        m_screenSyncTimer.start();
+        //QTimer::singleShot(2500, this, &DockView::reconsiderScreen);
 
         //if (found)
            // setScreenToFollow(m_screenToFollow);

app/dockview.h

@@ -197,6 +197,8 @@ private:
     QPointer<QScreen> m_screenToFollow;
     QString m_screenToFollowId;
 
+    QTimer m_screenSyncTimer;
+
     //only for the mask, not to actually paint
     Plasma::FrameSvg::EnabledBorders m_enabledBorders = Plasma::FrameSvg::AllBorders;
 };

shell/contents/configuration/BehaviorConfig.qml

@@ -57,6 +57,7 @@ PlasmaComponents.Page {
                 Layout.leftMargin: units.smallSpacing * 2
                 Layout.rightMargin: units.smallSpacing * 2
                 spacing: 1
+                visible: false
 
                 function updateScreens() {
                     if (dock.screens.length > 1)