diff --git a/src/core/krearrangecolumnsproxymodel.cpp b/src/core/krearrangecolumnsproxymodel.cpp
--- a/src/core/krearrangecolumnsproxymodel.cpp
+++ b/src/core/krearrangecolumnsproxymodel.cpp
@@ -25,7 +25,11 @@
 
 void KRearrangeColumnsProxyModel::setSourceColumns(const QVector<int> &columns)
 {
+    // We could use layoutChanged() here, but we would have to map persistent
+    // indexes from the old to the new location...
+    beginResetModel();
     d_ptr->m_sourceColumns = columns;
+    endResetModel();
 }
 
 int KRearrangeColumnsProxyModel::columnCount(const QModelIndex &parent) const
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -2,3 +2,20 @@
 remove_definitions(-DQT_NO_CAST_FROM_ASCII)
 
 add_subdirectory(proxymodeltestapp)
+
+find_package(Qt5Widgets ${REQUIRED_QT_VERSION} CONFIG)
+if (Qt5Widgets_FOUND)
+  macro(KITEMMODELS_WIDGETS_TESTS)
+    foreach(_testname ${ARGN})
+      add_executable(${_testname} ${_testname}.cpp)
+      target_link_libraries(${_testname}
+         KF5::ItemModels
+         Qt5::Widgets)
+      ecm_mark_as_test(${_testname})
+    endforeach()
+  endmacro(KITEMMODELS_WIDGETS_TESTS)
+
+  KITEMMODELS_WIDGETS_TESTS(
+    rearrangecolumns
+  )
+endif()
diff --git a/tests/rearrangecolumns.cpp b/tests/rearrangecolumns.cpp
new file mode 100644
--- /dev/null
+++ b/tests/rearrangecolumns.cpp
@@ -0,0 +1,41 @@
+#include <QApplication>
+#include <QTreeView>
+#include <KRearrangeColumnsProxyModel>
+#include <QStandardItemModel>
+#include <QTimer>
+
+// Prepares one row for a QStandardItemModel
+inline QList<QStandardItem *> makeStandardItems(const QStringList &texts)
+{
+    QList<QStandardItem *> items;
+    items.reserve(texts.count());
+    for (const QString &txt : texts) {
+        items << new QStandardItem(txt);
+    }
+    return items;
+}
+
+int main(int argc, char** argv)
+{
+    QApplication app(argc, argv);
+
+    QStandardItemModel source;
+    source.insertRow(0, makeStandardItems({QStringLiteral("A0"), QStringLiteral("B0"), QStringLiteral("C0"), QStringLiteral("D0")}));
+    source.insertRow(1, makeStandardItems({QStringLiteral("A1"), QStringLiteral("B1"), QStringLiteral("C1"), QStringLiteral("D1")}));
+    source.insertRow(2, makeStandardItems({QStringLiteral("A2"), QStringLiteral("B2"), QStringLiteral("C2"), QStringLiteral("D2")}));
+    source.setHorizontalHeaderLabels({QStringLiteral("H1"), QStringLiteral("H2"), QStringLiteral("H3"), QStringLiteral("H4")});
+
+    KRearrangeColumnsProxyModel pm;
+    pm.setSourceColumns(QVector<int>{2, 3, 1, 0});
+    pm.setSourceModel(&source);
+
+    QTreeView treeView;
+    treeView.setModel(&pm);
+    treeView.show();
+
+    QTimer::singleShot(500, &pm, [&]() {
+        pm.setSourceColumns(QVector<int>() << 2 << 1 << 0 << 3);
+    });
+
+    return app.exec();
+}