fix #116,add protections in multi-screen

app/dockcorona.cpp

@@ -211,6 +211,7 @@ QRect DockCorona::availableScreenRect(int id) const
                 case Plasma::Types::TopEdge:
                     available.setTopLeft({available.x(), dockRect.bottom()});
                     break;
+
                 case Plasma::Types::BottomEdge:
                     available.setBottomLeft({available.x(), dockRect.top()});
                     break;
@@ -302,7 +303,7 @@ QList<Plasma::Types::Location> DockCorona::freeEdges(int screen) const
 int DockCorona::screenForContainment(const Plasma::Containment *containment) const
 {
     for (auto *view : m_dockViews) {
-        if (view && view->containment() && view->containment()->id() == containment->id())
+        if (view && view->containment() && view->containment() == containment)
             if (view->screen())
                 return qGuiApp->screens().indexOf(view->screen());
     }

app/dockview.cpp

@@ -135,12 +135,15 @@ void DockView::init()
 
 void DockView::adaptToScreen(QScreen *screen)
 {
-    if (!screen || !containment()) {
+    if (!screen || !containment() || this->screen() == screen) {
         return;
     }
 
     setScreen(screen);
 
+    //FIXME:: This code in a multi-screen environment that
+    //primary screen is not set to 0 it creates an endless
+    //showing loop at startup (catch-up race) between screen:0 and primaryScreen
     if (containment())
         containment()->reactToScreenChange();
 
@@ -296,6 +299,7 @@ void DockView::updatePosition()
     switch (location()) {
         case Plasma::Types::TopEdge:
             screenGeometry = screen()->geometry();
+
             if (m_drawShadows) {
                 position = {screenGeometry.x() + length(screenGeometry.width()), screenGeometry.y()};
             } else {
@@ -306,6 +310,7 @@ void DockView::updatePosition()
 
         case Plasma::Types::BottomEdge:
             screenGeometry = screen()->geometry();
+
             if (m_drawShadows) {
                 position = {screenGeometry.x() + length(screenGeometry.width()),
                             screenGeometry.y() + screenGeometry.height() - cleanThickness
@@ -318,6 +323,7 @@ void DockView::updatePosition()
 
         case Plasma::Types::RightEdge:
             screenGeometry = corona()->availableScreenRect(containment()->screen());
+
             if (m_drawShadows && !mask().isNull()) {
                 position = {screenGeometry.x() + screenGeometry.width() - cleanThickness,
                             screenGeometry.y() + length(screenGeometry.height())
@@ -330,6 +336,7 @@ void DockView::updatePosition()
 
         case Plasma::Types::LeftEdge:
             screenGeometry = corona()->availableScreenRect(containment()->screen());
+
             if (m_drawShadows && !mask().isNull()) {
                 position = {screenGeometry.x(), screenGeometry.y() + length(screenGeometry.height())};
             } else {