Index: Riskeer/Integration/src/Riskeer.Integration.Plugin/RiskeerPlugin.cs
===================================================================
diff -u -r24ff1a991d8a2e42be8fc689b3c401c4c6ed7f5a -rea58bf4e2497098edf2125a0fb76c728beb2fd40
--- Riskeer/Integration/src/Riskeer.Integration.Plugin/RiskeerPlugin.cs	(.../RiskeerPlugin.cs)	(revision 24ff1a991d8a2e42be8fc689b3c401c4c6ed7f5a)
+++ Riskeer/Integration/src/Riskeer.Integration.Plugin/RiskeerPlugin.cs	(.../RiskeerPlugin.cs)	(revision ea58bf4e2497098edf2125a0fb76c728beb2fd40)
@@ -1328,9 +1328,9 @@
         private static bool WaterLevelCalculationsForUserDefinedTargetProbabilitiesGroupContext_CanDropOrInsert(object draggedData, object targetData)
         {
             var waterLevelCalculationsForTargetProbabilitiesGroupContext = (WaterLevelCalculationsForUserDefinedTargetProbabilitiesGroupContext) targetData;
-            var waterLevelCalculationsForTargetProbabilityContext = (WaterLevelCalculationsForUserDefinedTargetProbabilityContext) draggedData;
 
-            return waterLevelCalculationsForTargetProbabilitiesGroupContext.WrappedData.Contains(waterLevelCalculationsForTargetProbabilityContext.WrappedData);
+            return draggedData is WaterLevelCalculationsForUserDefinedTargetProbabilityContext waterLevelCalculationsForTargetProbabilityContext
+                   && waterLevelCalculationsForTargetProbabilitiesGroupContext.WrappedData.Contains(waterLevelCalculationsForTargetProbabilityContext.WrappedData);
         }
 
         private static void WaterLevelCalculationsForUserDefinedTargetProbabilitiesGroupContext_OnDrop(object droppedData, object newParentData, object oldParentData, int position, TreeViewControl treeViewControl)
Index: Riskeer/Integration/test/Riskeer.Integration.Plugin.Test/TreeNodeInfos/WaterLevelCalculationsForUserDefinedTargetProbabilitiesGroupContextTreeNodeInfoTest.cs
===================================================================
diff -u -r14c5f66501f9265a20bc042c0440d06d0df771fd -rea58bf4e2497098edf2125a0fb76c728beb2fd40
--- Riskeer/Integration/test/Riskeer.Integration.Plugin.Test/TreeNodeInfos/WaterLevelCalculationsForUserDefinedTargetProbabilitiesGroupContextTreeNodeInfoTest.cs	(.../WaterLevelCalculationsForUserDefinedTargetProbabilitiesGroupContextTreeNodeInfoTest.cs)	(revision 14c5f66501f9265a20bc042c0440d06d0df771fd)
+++ Riskeer/Integration/test/Riskeer.Integration.Plugin.Test/TreeNodeInfos/WaterLevelCalculationsForUserDefinedTargetProbabilitiesGroupContextTreeNodeInfoTest.cs	(.../WaterLevelCalculationsForUserDefinedTargetProbabilitiesGroupContextTreeNodeInfoTest.cs)	(revision ea58bf4e2497098edf2125a0fb76c728beb2fd40)
@@ -86,9 +86,9 @@
                 Assert.IsNull(info.CheckedState);
                 Assert.IsNull(info.OnNodeChecked);
                 Assert.IsNull(info.CanDrag);
-                Assert.IsNull(info.CanDrop);
-                Assert.IsNull(info.CanInsert);
-                Assert.IsNull(info.OnDrop);
+                Assert.IsNotNull(info.CanDrop);
+                Assert.IsNotNull(info.CanInsert);
+                Assert.IsNotNull(info.OnDrop);
             }
         }
 
@@ -776,6 +776,200 @@
             mockRepository.VerifyAll();
         }
 
+        [Test]
+        public void CanInsert_DraggedDataOfUnsupportedDataType_ReturnsFalse()
+        {
+            // Setup
+            using (var plugin = new RiskeerPlugin())
+            {
+                TreeNodeInfo info = GetInfo(plugin);
+
+                var targetData = new WaterLevelCalculationsForUserDefinedTargetProbabilitiesGroupContext(
+                    new ObservableList<HydraulicBoundaryLocationCalculationsForTargetProbability>(),
+                    new AssessmentSectionStub());
+
+                // Call
+                bool canInsert = info.CanInsert(new object(), targetData);
+
+                // Assert
+                Assert.IsFalse(canInsert);
+            }
+        }
+
+        [Test]
+        public void CanInsert_DraggedDataNotPartOfGroupContext_ReturnsFalse()
+        {
+            // Setup
+            using (var plugin = new RiskeerPlugin())
+            {
+                TreeNodeInfo info = GetInfo(plugin);
+
+                var assessmentSectionStub = new AssessmentSectionStub();
+
+                var targetData = new WaterLevelCalculationsForUserDefinedTargetProbabilitiesGroupContext(
+                    new ObservableList<HydraulicBoundaryLocationCalculationsForTargetProbability>(),
+                    assessmentSectionStub);
+
+                var draggedData = new WaterLevelCalculationsForUserDefinedTargetProbabilityContext(
+                    new HydraulicBoundaryLocationCalculationsForTargetProbability(),
+                    assessmentSectionStub);
+
+                // Call
+                bool canInsert = info.CanInsert(draggedData, targetData);
+
+                // Assert
+                Assert.IsFalse(canInsert);
+            }
+        }
+
+        [Test]
+        public void CanInsert_DraggedDataPartOfGroupContext_ReturnsTrue()
+        {
+            // Setup
+            using (var plugin = new RiskeerPlugin())
+            {
+                TreeNodeInfo info = GetInfo(plugin);
+
+                var assessmentSectionStub = new AssessmentSectionStub();
+                var calculationsForTargetProbability = new HydraulicBoundaryLocationCalculationsForTargetProbability();
+
+                var targetData = new WaterLevelCalculationsForUserDefinedTargetProbabilitiesGroupContext(
+                    new ObservableList<HydraulicBoundaryLocationCalculationsForTargetProbability>
+                    {
+                        calculationsForTargetProbability
+                    },
+                    assessmentSectionStub);
+
+                var draggedData = new WaterLevelCalculationsForUserDefinedTargetProbabilityContext(
+                    calculationsForTargetProbability,
+                    assessmentSectionStub);
+
+                // Call
+                bool canInsert = info.CanInsert(draggedData, targetData);
+
+                // Assert
+                Assert.IsTrue(canInsert);
+            }
+        }
+
+        [Test]
+        public void CanDrop_DraggedDataOfUnsupportedDataType_ReturnsFalse()
+        {
+            // Setup
+            using (var plugin = new RiskeerPlugin())
+            {
+                TreeNodeInfo info = GetInfo(plugin);
+
+                var targetData = new WaterLevelCalculationsForUserDefinedTargetProbabilitiesGroupContext(
+                    new ObservableList<HydraulicBoundaryLocationCalculationsForTargetProbability>(),
+                    new AssessmentSectionStub());
+
+                // Call
+                bool canDrop = info.CanDrop(new object(), targetData);
+
+                // Assert
+                Assert.IsFalse(canDrop);
+            }
+        }
+
+        [Test]
+        public void CanDrop_DraggedDataNotPartOfGroupContext_ReturnsFalse()
+        {
+            // Setup
+            using (var plugin = new RiskeerPlugin())
+            {
+                TreeNodeInfo info = GetInfo(plugin);
+
+                var assessmentSectionStub = new AssessmentSectionStub();
+
+                var targetData = new WaterLevelCalculationsForUserDefinedTargetProbabilitiesGroupContext(
+                    new ObservableList<HydraulicBoundaryLocationCalculationsForTargetProbability>(),
+                    assessmentSectionStub);
+
+                var draggedData = new WaterLevelCalculationsForUserDefinedTargetProbabilityContext(
+                    new HydraulicBoundaryLocationCalculationsForTargetProbability(),
+                    assessmentSectionStub);
+
+                // Call
+                bool canDrop = info.CanDrop(draggedData, targetData);
+
+                // Assert
+                Assert.IsFalse(canDrop);
+            }
+        }
+
+        [Test]
+        public void CanDrop_DraggedDataPartOfGroupContext_ReturnsTrue()
+        {
+            // Setup
+            using (var plugin = new RiskeerPlugin())
+            {
+                TreeNodeInfo info = GetInfo(plugin);
+
+                var assessmentSectionStub = new AssessmentSectionStub();
+                var calculationsForTargetProbability = new HydraulicBoundaryLocationCalculationsForTargetProbability();
+
+                var targetData = new WaterLevelCalculationsForUserDefinedTargetProbabilitiesGroupContext(
+                    new ObservableList<HydraulicBoundaryLocationCalculationsForTargetProbability>
+                    {
+                        calculationsForTargetProbability
+                    },
+                    assessmentSectionStub);
+
+                var draggedData = new WaterLevelCalculationsForUserDefinedTargetProbabilityContext(
+                    calculationsForTargetProbability,
+                    assessmentSectionStub);
+
+                // Call
+                bool canDrop = info.CanDrop(draggedData, targetData);
+
+                // Assert
+                Assert.IsTrue(canDrop);
+            }
+        }
+
+        [Test]
+        public void OnDrop_DataDroppedToDifferentIndex_DroppedDataCorrectlyMoved()
+        {
+            // Setup
+            using (var plugin = new RiskeerPlugin())
+            {
+                TreeNodeInfo info = GetInfo(plugin);
+
+                var assessmentSectionStub = new AssessmentSectionStub();
+
+                var calculationsForTargetProbability1 = new HydraulicBoundaryLocationCalculationsForTargetProbability();
+                var calculationsForTargetProbability2 = new HydraulicBoundaryLocationCalculationsForTargetProbability();
+                var calculationsForTargetProbability3 = new HydraulicBoundaryLocationCalculationsForTargetProbability();
+
+                var calculationsForTargetProbabilities = new ObservableList<HydraulicBoundaryLocationCalculationsForTargetProbability>
+                {
+                    calculationsForTargetProbability1,
+                    calculationsForTargetProbability2,
+                    calculationsForTargetProbability3
+                };
+
+                var parentData = new WaterLevelCalculationsForUserDefinedTargetProbabilitiesGroupContext(
+                    calculationsForTargetProbabilities,
+                    assessmentSectionStub);
+
+                var droppedData = new WaterLevelCalculationsForUserDefinedTargetProbabilityContext(
+                    calculationsForTargetProbability3,
+                    assessmentSectionStub);
+
+                // Call
+                info.OnDrop(droppedData, parentData, parentData, 1, null);
+
+                // Assert
+                CollectionAssert.AreEquivalent(new[]
+                {
+                    calculationsForTargetProbability1,
+                    calculationsForTargetProbability3,
+                    calculationsForTargetProbability2
+                }, calculationsForTargetProbabilities);
+            }
+        }
+
         private static void AssertHydraulicBoundaryLocationCalculationOutput(IDesignWaterLevelCalculator designWaterLevelCalculator,
                                                                              HydraulicBoundaryLocationCalculationOutput actualOutput)
         {