diff --git a/containments/desktop/plugins/folder/autotests/positionertest.h b/containments/desktop/plugins/folder/autotests/positionertest.h
--- a/containments/desktop/plugins/folder/autotests/positionertest.h
+++ b/containments/desktop/plugins/folder/autotests/positionertest.h
@@ -52,6 +52,7 @@
     void tst_defaultValues();
     void tst_changeEnabledStatus();
     void tst_changePerStripe();
+    void tst_proxyMapping();
 
 private:
     void checkPositions(int perStripe);
diff --git a/containments/desktop/plugins/folder/autotests/positionertest.cpp b/containments/desktop/plugins/folder/autotests/positionertest.cpp
--- a/containments/desktop/plugins/folder/autotests/positionertest.cpp
+++ b/containments/desktop/plugins/folder/autotests/positionertest.cpp
@@ -29,6 +29,7 @@
 
 #include "foldermodel.h"
 #include "positioner.h"
+#include "screenmapper.h"
 
 QTEST_MAIN(PositionerTest)
 
@@ -58,6 +59,9 @@
 void PositionerTest::init()
 {
     m_folderModel = new FolderModel(this);
+    m_folderModel->setScreen(0);
+    m_folderModel->setScreenMapper(ScreenMapper::instance());
+    m_folderModel->setUsedByContainment(true);
     m_positioner = new Positioner(this);
     m_positioner->setEnabled(true);
     m_positioner->setFolderModel(m_folderModel);
@@ -209,6 +213,98 @@
     QCOMPARE(s.count(), 2);
 }
 
+void PositionerTest::tst_proxyMapping()
+{
+    auto *screenMapper = ScreenMapper::instance();
+    FolderModel secondFolderModel;
+    secondFolderModel.setUrl(m_folderDir->path()  + QDir::separator() + desktop );
+    secondFolderModel.setUsedByContainment(true);
+    secondFolderModel.setScreenMapper(screenMapper);
+    secondFolderModel.setScreen(1);
+    Positioner secondPositioner;
+    secondPositioner.setEnabled(true);
+    secondPositioner.setFolderModel(&secondFolderModel);
+    secondPositioner.setPerStripe(3);
+
+    QSignalSpy s2(&secondFolderModel, &FolderModel::listingCompleted);
+    QVERIFY(s2.wait(1000));
+
+    QHash<int, int> expectedSource2ProxyScreen0;
+    QHash<int, int> expectedProxy2SourceScreen0;
+    QHash<int, int> expectedProxy2SourceScreen1;
+    QHash<int, int> expectedSource2ProxyScreen1;
+
+    for (int i = 0; i < m_folderModel->rowCount(); i++) {
+        expectedSource2ProxyScreen0[i] = i;
+        expectedProxy2SourceScreen0[i] = i;
+    }
+
+    // swap items 1 and 2 in the positioner
+    m_positioner->move({1, 2, 2, 1});
+    expectedSource2ProxyScreen0[1] = 2;
+    expectedSource2ProxyScreen0[2] = 1;
+    expectedProxy2SourceScreen0[1] = 2;
+    expectedProxy2SourceScreen0[2] = 1;
+
+    auto savedSource2ProxyScreen0 = expectedSource2ProxyScreen0;
+    auto savedProxy2SourceScreen0 = expectedProxy2SourceScreen0;
+
+    auto verifyMapping = [](const QHash<int, int> &actual, const QHash<int, int> &expected) {
+
+        auto ensureUnique = [](const QHash<int, int> mapping) {
+            auto values = mapping.values();
+            qSort(values);
+            auto uniqueValues = values.toSet().toList();
+            qSort(uniqueValues);
+            QVERIFY(uniqueValues == values);
+        };
+
+        ensureUnique(actual);
+        QCOMPARE(actual, expected);
+    };
+
+    verifyMapping(m_positioner->proxyToSourceMapping(), expectedProxy2SourceScreen0);
+    verifyMapping(m_positioner->sourceToProxyMapping(), expectedSource2ProxyScreen0);
+    verifyMapping(secondPositioner.proxyToSourceMapping(), expectedProxy2SourceScreen1);
+    verifyMapping(secondPositioner.sourceToProxyMapping(), expectedSource2ProxyScreen1);
+
+    const auto movedItem = m_folderModel->index(1, 0).data(FolderModel::UrlRole).toString();
+
+    // move the item 1 from source (now in position 2) to the second screen
+    screenMapper->addMapping(movedItem, 1);
+
+    expectedProxy2SourceScreen1[0] = 0;
+    expectedSource2ProxyScreen1[0] = 0;
+    expectedSource2ProxyScreen0.clear();
+    expectedProxy2SourceScreen0.clear();
+    for (int i = 0; i < m_folderModel->rowCount(); i++) {
+        // as item 1 disappeared, the mapping of all items after that are shifted
+        auto proxyIndex = (i <= 1) ? i : i + 1;
+        expectedProxy2SourceScreen0[proxyIndex] = i;
+        expectedSource2ProxyScreen0[i] = proxyIndex;
+    }
+
+    verifyMapping(m_positioner->proxyToSourceMapping(), expectedProxy2SourceScreen0);
+    verifyMapping(m_positioner->sourceToProxyMapping(), expectedSource2ProxyScreen0);
+    verifyMapping(secondPositioner.proxyToSourceMapping(), expectedProxy2SourceScreen1);
+    verifyMapping(secondPositioner.sourceToProxyMapping(), expectedSource2ProxyScreen1);
+
+    // move back the same item to the first screen
+    screenMapper->addMapping(movedItem, 0);
+
+    // nothing on the second screen
+    expectedSource2ProxyScreen1.clear();
+    expectedProxy2SourceScreen1.clear();
+    // first screen should look like in the beginning
+    expectedSource2ProxyScreen0 = savedSource2ProxyScreen0;
+    expectedProxy2SourceScreen0 = savedProxy2SourceScreen0;
+
+    verifyMapping(m_positioner->proxyToSourceMapping(), expectedProxy2SourceScreen0);
+    verifyMapping(m_positioner->sourceToProxyMapping(), expectedSource2ProxyScreen0);
+    verifyMapping(secondPositioner.proxyToSourceMapping(), expectedProxy2SourceScreen1);
+    verifyMapping(secondPositioner.sourceToProxyMapping(), expectedSource2ProxyScreen1);
+}
+
 void PositionerTest::checkPositions(int perStripe)
 {
     QSignalSpy s(m_positioner, &Positioner::positionsChanged);
diff --git a/containments/desktop/plugins/folder/positioner.h b/containments/desktop/plugins/folder/positioner.h
--- a/containments/desktop/plugins/folder/positioner.h
+++ b/containments/desktop/plugins/folder/positioner.h
@@ -76,6 +76,15 @@
         int rowCount(const QModelIndex &parent = QModelIndex()) const override;
         int columnCount(const QModelIndex &parent = QModelIndex()) const override;
 
+#ifdef BUILD_TESTING
+        QHash<int, int> proxyToSourceMapping() const {
+            return m_proxyToSource;
+        }
+        QHash<int, int> sourceToProxyMapping() const {
+            return m_sourceToProxy;
+        }
+#endif
+
     Q_SIGNALS:
         void enabledChanged() const;
         void folderModelChanged() const;
@@ -128,6 +137,7 @@
 
         QHash<int, int> m_proxyToSource;
         QHash<int, int> m_sourceToProxy;
+        bool m_beginInsertRowsCalled = false; // used to sync the amount of begin/endInsertRows calls
 };
 
 #endif
diff --git a/containments/desktop/plugins/folder/positioner.cpp b/containments/desktop/plugins/folder/positioner.cpp
--- a/containments/desktop/plugins/folder/positioner.cpp
+++ b/containments/desktop/plugins/folder/positioner.cpp
@@ -425,6 +425,10 @@
     const int newCount = rowCount();
 
     if (newCount > oldCount) {
+        if (m_beginInsertRowsCalled) {
+            endInsertRows();
+            m_beginInsertRowsCalled = false;
+        }
         beginInsertRows(QModelIndex(), oldCount, newCount - 1);
         endInsertRows();
     }
@@ -510,14 +514,28 @@
     if (m_enabled) {
         if (m_proxyToSource.isEmpty()) {
             if (!m_pendingPositions) {
-                emit beginInsertRows(parent, start, end);
+                beginInsertRows(parent, start, end);
+                m_beginInsertRowsCalled = true;
 
                 initMaps(end + 1);
             }
 
             return;
         }
 
+        // When new rows are inserted, they might go in the beginning or in the middle.
+        // In this case we must update first the existing proxy->source and source->proxy
+        // mapping, otherwise the proxy items will point to the wrong source item.
+        int count = end - start + 1;
+        m_sourceToProxy.clear();
+        for (auto it = m_proxyToSource.begin(); it != m_proxyToSource.end(); ++it) {
+            int sourceIdx = *it;
+            if (sourceIdx >= start) {
+                *it += count;
+            }
+            m_sourceToProxy[*it] = it.key();
+        }
+
         int free = -1;
         int rest = -1;
 
@@ -538,6 +556,7 @@
             int remainder = (end - rest);
 
             beginInsertRows(parent, firstNew, firstNew + remainder);
+            m_beginInsertRowsCalled = true;
 
             for (int i = 0; i <= remainder; ++i) {
                 updateMaps(firstNew + i, rest + i);
@@ -547,6 +566,8 @@
         }
     } else {
         emit beginInsertRows(parent, start, end);
+        beginInsertRows(parent, start, end);
+        m_beginInsertRowsCalled = true;
     }
 }
 
@@ -617,7 +638,10 @@
 
     if (!m_ignoreNextTransaction) {
         if (!m_pendingPositions) {
-            emit endInsertRows();
+            if (m_beginInsertRowsCalled) {
+                endInsertRows();
+                m_beginInsertRowsCalled = false;
+            }
         } else {
             applyPositions();
         }