fix #532,dont allow to add a second Tasks plasmoid

app/dockview.cpp

@@ -1180,6 +1180,29 @@ bool DockView::tasksPresent()
     return false;
 }
 
+//!check if the plasmoid with _name_ exists in the midedata
+bool DockView::mimeContainsPlasmoid(QMimeData *mimeData, QString name)
+{
+    if (!mimeData) {
+        return false;
+    }
+
+    if (mimeData->hasFormat(QStringLiteral("text/x-plasmoidservicename"))) {
+        QString data = mimeData->data(QStringLiteral("text/x-plasmoidservicename"));
+        const QStringList appletNames = data.split('\n', QString::SkipEmptyParts);
+
+        foreach (const QString &appletName, appletNames) {
+            qDebug() << "adding" << appletName;
+
+            if (appletName == name)
+                return true;
+        }
+    }
+
+    return false;
+}
+
+
 VisibilityManager *DockView::visibility() const
 {
     return m_visibility;

app/dockview.h

@@ -29,6 +29,7 @@
 #include <QQuickView>
 #include <QQmlListProperty>
 #include <QMenu>
+#include <QMimeData>
 #include <QScreen>
 #include <QPointer>
 #include <QTimer>
@@ -165,14 +166,18 @@ public slots:
 
     Q_INVOKABLE QList<int> freeEdges() const;
     Q_INVOKABLE QVariantList containmentActions();
-    Q_INVOKABLE int docksWithTasks();
+
     Q_INVOKABLE void deactivateApplets();
     Q_INVOKABLE void removeTasksPlasmoid();
-    Q_INVOKABLE bool setCurrentScreen(const QString id);
-    Q_INVOKABLE bool tasksPresent();
     Q_INVOKABLE void toggleAppletExpanded(const int id);
     Q_INVOKABLE void updateEnabledBorders();
 
+    Q_INVOKABLE int docksWithTasks();
+
+    Q_INVOKABLE bool mimeContainsPlasmoid(QMimeData *mimeData, QString name);
+    Q_INVOKABLE bool setCurrentScreen(const QString id);
+    Q_INVOKABLE bool tasksPresent();
+
     Q_INVOKABLE void closeApplication();
 
     void updateAbsDockGeometry(bool bypassChecks = false);

containment/package/contents/ui/main.qml

@@ -378,10 +378,10 @@ DragDrop.DropArea {
             slotAnimationsNeedLength(1);
         }
 
-        //var relevantLayout = layoutsContainer.mainLayout.mapFromItem(root, event.x, event.y);
-        //LayoutManager.insertAtCoordinates2(dndSpacer, relevantLayout.x, relevantLayout.y)
-        LayoutManager.insertAtCoordinates2(dndSpacer, event.x, event.y)
-        dndSpacer.opacity = 1;
+        if (!latteApplet || (latteApplet && !dock.mimeContainsPlasmoid(event.mimeData, "org.kde.latte.plasmoid"))) {
+            LayoutManager.insertAtCoordinates2(dndSpacer, event.x, event.y)
+            dndSpacer.opacity = 1;
+        }
     }
 
     onDragMove: {
@@ -398,10 +398,10 @@ DragDrop.DropArea {
             }
         }
 
-        //var relevantLayout = layoutsContainer.mainLayout.mapFromItem(root, event.x, event.y);
-        //LayoutManager.insertAtCoordinates2(dndSpacer, relevantLayout.x, relevantLayout.y)
-        LayoutManager.insertAtCoordinates2(dndSpacer, event.x, event.y)
-        dndSpacer.opacity = 1;
+        if (!latteApplet || (latteApplet && !dock.mimeContainsPlasmoid(event.mimeData, "org.kde.latte.plasmoid"))) {
+            LayoutManager.insertAtCoordinates2(dndSpacer, event.x, event.y)
+            dndSpacer.opacity = 1;
+        }
     }
 
     onDragLeave: {
@@ -423,7 +423,7 @@ DragDrop.DropArea {
         if (event.mimeData.formats.indexOf("application/x-orgkdeplasmataskmanager_taskbuttonitem") < 0) {
             if (latteApplet && latteApplet.launchersDrop(event) && root.addLaunchersInTaskManager) {
                 latteApplet.launchersDropped(event.mimeData.urls);
-            } else {
+            } else if (!latteApplet || (latteApplet && !dock.mimeContainsPlasmoid(event.mimeData, "org.kde.latte.plasmoid"))) {
                 plasmoid.processMimeData(event.mimeData, event.x, event.y);
                 event.accept(event.proposedAction);
             }