diff --git a/core/keyboard_nav/navigation.js b/core/keyboard_nav/navigation.js
index c3247aa78..1385bc38c 100644
--- a/core/keyboard_nav/navigation.js
+++ b/core/keyboard_nav/navigation.js
@@ -385,7 +385,7 @@ Blockly.navigation.insertFromFlyout = function() {
   newBlock.setConnectionsHidden(false);
   Blockly.navigation.cursor_.setLocation(
       Blockly.ASTNode.createBlockNode(newBlock));
-  if (!Blockly.navigation.modify()) {
+  if (!Blockly.navigation.modify_()) {
     Blockly.navigation.warn('Something went wrong while inserting a block from the flyout.');
   }
 
@@ -412,11 +412,12 @@ Blockly.navigation.resetFlyout = function(shouldHide) {
 /************/
 
 /**
- * Handle the modifier key (currently I for Insert).
- * @return {boolean} True if the key was handled; false if something went wrong.
- * @package
+ * Warns the user if the cursor or marker is on a type that can not be connected.
+ * @return {boolean} True if the marker and cursor are valid types, false
+ *     otherwise.
+ * @private
  */
-Blockly.navigation.modify = function() {
+Blockly.navigation.modifyWarn_ = function() {
   var markerNode = Blockly.navigation.marker_.getCurNode();
   var cursorNode = Blockly.navigation.cursor_.getCurNode();
 
@@ -432,68 +433,83 @@ Blockly.navigation.modify = function() {
   var markerType = markerNode.getType();
   var cursorType = cursorNode.getType();
 
+  // Check the marker for invalid types.
   if (markerType == Blockly.ASTNode.types.FIELD) {
     Blockly.navigation.warn('Should not have been able to mark a field.');
     return false;
-  }
-  if (markerType == Blockly.ASTNode.types.BLOCK) {
+  } else if (markerType == Blockly.ASTNode.types.BLOCK) {
     Blockly.navigation.warn('Should not have been able to mark a block.');
     return false;
-  }
-  if (markerType == Blockly.ASTNode.types.STACK) {
+  } else if (markerType == Blockly.ASTNode.types.STACK) {
     Blockly.navigation.warn('Should not have been able to mark a stack.');
     return false;
   }
 
+  // Check the cursor for invalid types.
   if (cursorType == Blockly.ASTNode.types.FIELD) {
     Blockly.navigation.warn('Cannot attach a field to anything else.');
     return false;
-  }
-
-  if (cursorType == Blockly.ASTNode.types.WORKSPACE) {
+  } else if (cursorType == Blockly.ASTNode.types.WORKSPACE) {
     Blockly.navigation.warn('Cannot attach a workspace to anything else.');
     return false;
   }
+  return true;
+};
+
+/**
+ * Disconnect the block from its parent and move to the position of the
+ * workspace node.
+ * @param {!Blockly.Block} block The block to be moved to the workspace.
+ * @param {!Blockly.ASTNode} wsNode The workspace node holding the position the
+ *     block will be moved to.
+ * @return {boolean} True if the block can be moved to the workspace,
+ *     false otherwise.
+ * @private
+ */
+Blockly.navigation.moveBlockToWorkspace_ = function(block, wsNode) {
+  if (block.isShadow()) {
+    Blockly.navigation.warn('Cannot move a shadow block to the workspace.');
+    return false;
+  }
+  if (block.getParent()) {
+    block.unplug(false);
+  }
+  block.moveTo(wsNode.getWsCoordinate());
+  return true;
+};
+
+/**
+ * Handle the modifier key (currently I for Insert).
+ * Tries to connect the current marker and cursor location. Warns the user if
+ * the two locations can not be connected.
+ * @return {boolean} True if the key was handled; false if something went wrong.
+ * @private
+ */
+Blockly.navigation.modify_ = function() {
+  var markerNode = Blockly.navigation.marker_.getCurNode();
+  var cursorNode = Blockly.navigation.cursor_.getCurNode();
+  if (!Blockly.navigation.modifyWarn_()) {
+    return false;
+  }
+
+  var markerType = markerNode.getType();
+  var cursorType = cursorNode.getType();
 
   var cursorLoc = cursorNode.getLocation();
   var markerLoc = markerNode.getLocation();
 
-  if (markerNode.isConnection()) {
-    // TODO: Handle the case when one or both are already connected.
-    if (cursorNode.isConnection()) {
-      return Blockly.navigation.connect(cursorLoc, markerLoc);
-    } else if (cursorType == Blockly.ASTNode.types.BLOCK ||
-        cursorType == Blockly.ASTNode.types.STACK) {
-      return Blockly.navigation.insertBlock(cursorLoc, markerLoc);
-    }
+  if (markerNode.isConnection() && cursorNode.isConnection()) {
+    return Blockly.navigation.connect(cursorLoc, markerLoc);
+  } else if (markerNode.isConnection() &&
+        (cursorType == Blockly.ASTNode.types.BLOCK ||
+        cursorType == Blockly.ASTNode.types.STACK)) {
+    return Blockly.navigation.insertBlock(cursorLoc, markerLoc);
   } else if (markerType == Blockly.ASTNode.types.WORKSPACE) {
-    if (cursorNode.isConnection()) {
-      if (cursorType == Blockly.ASTNode.types.INPUT ||
-          cursorType == Blockly.ASTNode.types.NEXT) {
-        Blockly.navigation.warn(
-            'Cannot move a next or input connection to the workspace.');
-        return false;
-      }
-      var block = cursorLoc.getSourceBlock();
-    } else if (cursorType == Blockly.ASTNode.types.BLOCK ||
-        cursorType == Blockly.ASTNode.types.STACK) {
-      var block = cursorLoc;
-    } else {
-      return false;
-    }
-    if (block.isShadow()) {
-      Blockly.navigation.warn('Cannot move a shadow block to the workspace.');
-      return false;
-    }
-    if (block.getParent()) {
-      block.unplug(false);
-    }
-    block.moveTo(markerNode.getWsCoordinate());
-    return true;
+    var block = Blockly.navigation.getSourceBlock_(cursorNode);
+    return Blockly.navigation.moveBlockToWorkspace_(block, markerNode);
   }
-  Blockly.navigation.warn('Unexpected state in Blockly.navigation.modify.');
+  Blockly.navigation.warn('Unexpected state in Blockly.navigation.modify_.');
   return false;
-  // TODO: Make sure the cursor and marker end up in the right places.
 };
 
 /**
@@ -768,8 +784,9 @@ Blockly.navigation.getSourceBlock_ = function(node) {
   }
   if (node.getType() === Blockly.ASTNode.types.BLOCK) {
     return node.getLocation();
-  } else if (node.getType() === Blockly.ASTNode.types.WORKSPACE ||
-      node.getType() === Blockly.ASTNode.types.STACK) {
+  } else if (node.getType() === Blockly.ASTNode.types.STACK) {
+    return node.getLocation();
+  } else if (node.getType() === Blockly.ASTNode.types.WORKSPACE) {
     return null;
   } else {
     return node.getLocation().getSourceBlock();
@@ -894,7 +911,7 @@ Blockly.navigation.workspaceOnAction_ = function(action) {
       Blockly.navigation.cursor_.in();
       return true;
     case Blockly.navigation.actionNames.INSERT:
-      Blockly.navigation.modify();
+      Blockly.navigation.modify_();
       return true;
     case Blockly.navigation.actionNames.MARK:
       Blockly.navigation.handleEnterForWS();
diff --git a/tests/mocha/.eslintrc.json b/tests/mocha/.eslintrc.json
index 8d4e9ecf7..b4bb40fec 100644
--- a/tests/mocha/.eslintrc.json
+++ b/tests/mocha/.eslintrc.json
@@ -15,7 +15,8 @@
         "assertUndefined": true,
         "assertNotUndefined": true,
         "defineStackBlock": true,
-        "defineRowBlock": true
+        "defineRowBlock": true,
+        "defineStatementBlock": true
 
     },
     "extends": "../../.eslintrc.json"
diff --git a/tests/mocha/navigation_modify_test.js b/tests/mocha/navigation_modify_test.js
index 8ffe834f4..4f6f25594 100644
--- a/tests/mocha/navigation_modify_test.js
+++ b/tests/mocha/navigation_modify_test.js
@@ -5,9 +5,12 @@ suite('Insert/Modify', function() {
       '<block type="stack_block" id="stack_block_2" x="12" y="113"></block>' +
       '<block type="row_block" id="row_block_1" x="13" y="213"></block>' +
       '<block type="row_block" id="row_block_2" x="12" y="288"></block>' +
+      '<block type="statement_block" id="statement_block_1" x="12" y="288"></block>' +
+      '<block type="statement_block" id="statement_block_2" x="12" y="288"></block>' +
     '</xml>';
     defineStackBlock();
     defineRowBlock();
+    defineStatementBlock();
 
     var toolbox = document.getElementById('toolbox-connections');
     this.workspace = Blockly.inject('blocklyDiv', {toolbox: toolbox});
@@ -17,6 +20,8 @@ suite('Insert/Modify', function() {
     this.stack_block_2 = this.workspace.getBlockById('stack_block_2');
     this.row_block_1 = this.workspace.getBlockById('row_block_1');
     this.row_block_2 = this.workspace.getBlockById('row_block_2');
+    this.statement_block_1 = this.workspace.getBlockById('statement_block_1');
+    this.statement_block_2 = this.workspace.getBlockById('statement_block_2');
 
     Blockly.navigation.enableKeyboardAccessibility();
     Blockly.navigation.focusWorkspace();
@@ -25,9 +30,8 @@ suite('Insert/Modify', function() {
   teardown(function() {
     delete Blockly.Blocks['stack_block'];
     delete Blockly.Blocks['row_block'];
+    delete Blockly.Blocks['statement_block'];
     this.workspace.dispose();
-    // Does disposing of the workspace dispose of cursors and markers
-    // correctly?
   });
 
   suite('Marked Connection', function() {
@@ -42,13 +46,13 @@ suite('Insert/Modify', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createWorkspaceNode(this.workspace,
                 new Blockly.utils.Coordinate(0, 0)));
-        chai.assert.isFalse(Blockly.navigation.modify());
+        chai.assert.isFalse(Blockly.navigation.modify_());
       });
       test('Cursor on compatible connection', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createConnectionNode(
                 this.stack_block_2.previousConnection));
-        chai.assert.isTrue(Blockly.navigation.modify());
+        chai.assert.isTrue(Blockly.navigation.modify_());
         chai.assert.equal(this.stack_block_1.getNextBlock().id, 'stack_block_2');
       });
       test('Cursor on incompatible connection', function() {
@@ -57,21 +61,21 @@ suite('Insert/Modify', function() {
                 this.stack_block_2.nextConnection));
         // Connect method will try to find a way to connect blocks with
         // incompatible types.
-        chai.assert.isTrue(Blockly.navigation.modify());
+        chai.assert.isTrue(Blockly.navigation.modify_());
         chai.assert.equal(this.stack_block_1.getNextBlock(), this.stack_block_2);
       });
       test('Cursor on really incompatible connection', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createConnectionNode(
                 this.row_block_1.outputConnection));
-        chai.assert.isFalse(Blockly.navigation.modify());
+        chai.assert.isFalse(Blockly.navigation.modify_());
         chai.assert.isNull(this.stack_block_1.getNextBlock());
       });
       test('Cursor on block', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createBlockNode(
                 this.stack_block_2));
-        chai.assert.isTrue(Blockly.navigation.modify());
+        chai.assert.isTrue(Blockly.navigation.modify_());
         chai.assert.equal(this.stack_block_1.getNextBlock().id, 'stack_block_2');
       });
     });
@@ -86,35 +90,35 @@ suite('Insert/Modify', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createConnectionNode(
                 this.stack_block_2.nextConnection));
-        chai.assert.isTrue(Blockly.navigation.modify());
+        chai.assert.isTrue(Blockly.navigation.modify_());
         chai.assert.equal(this.stack_block_1.getPreviousBlock().id, 'stack_block_2');
       });
       test('Cursor on incompatible connection', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createConnectionNode(
                 this.stack_block_2.previousConnection));
-        chai.assert.isFalse(Blockly.navigation.modify());
+        chai.assert.isFalse(Blockly.navigation.modify_());
         chai.assert.isNull(this.stack_block_1.getPreviousBlock());
       });
       test('Cursor on really incompatible connection', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createConnectionNode(
                 this.row_block_1.outputConnection));
-        chai.assert.isFalse(Blockly.navigation.modify());
+        chai.assert.isFalse(Blockly.navigation.modify_());
         chai.assert.isNull(this.stack_block_1.getNextBlock());
       });
       test('Cursor on block', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createBlockNode(
                 this.stack_block_2));
-        chai.assert.isTrue(Blockly.navigation.modify());
+        chai.assert.isTrue(Blockly.navigation.modify_());
         chai.assert.equal(this.stack_block_1.getPreviousBlock().id, 'stack_block_2');
       });
       test('Cursor on incompatible block', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createBlockNode(
                 this.row_block_1));
-        chai.assert.isFalse(Blockly.navigation.modify());
+        chai.assert.isFalse(Blockly.navigation.modify_());
         chai.assert.isNull(this.stack_block_1.getPreviousBlock());
       });
     });
@@ -129,7 +133,7 @@ suite('Insert/Modify', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createConnectionNode(
                 this.row_block_2.outputConnection));
-        chai.assert.isTrue(Blockly.navigation.modify());
+        chai.assert.isTrue(Blockly.navigation.modify_());
         chai.assert.equal(this.row_block_2.getParent().id, 'row_block_1');
       });
       test('Cursor on incompatible connection', function() {
@@ -138,7 +142,7 @@ suite('Insert/Modify', function() {
                 this.row_block_2.inputList[0].connection));
         // Connect method will try to find a way to connect blocks with
         // incompatible types.
-        chai.assert.isTrue(Blockly.navigation.modify());
+        chai.assert.isTrue(Blockly.navigation.modify_());
         chai.assert.equal(this.row_block_1.inputList[0].connection.targetBlock(),
             this.row_block_2);
       });
@@ -146,19 +150,49 @@ suite('Insert/Modify', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createConnectionNode(
                 this.stack_block_1.previousConnection));
-        chai.assert.isFalse(Blockly.navigation.modify());
+        chai.assert.isFalse(Blockly.navigation.modify_());
       });
       test('Cursor on block', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createBlockNode(
                 this.row_block_2));
-        chai.assert.isTrue(Blockly.navigation.modify());
+        chai.assert.isTrue(Blockly.navigation.modify_());
         chai.assert.equal(this.row_block_2.getParent().id, 'row_block_1');
       });
     });
 
-    suite('Statement input', function() {
-      // TODO: fill this out.
+    suite('Marked Statement input', function() {
+      setup(function() {
+        this.statement_block_1.inputList[0].connection.connect(
+            this.stack_block_1.previousConnection);
+        this.stack_block_1.nextConnection.connect(this.stack_block_2.previousConnection);
+        Blockly.navigation.marker_.setLocation(
+            Blockly.ASTNode.createInputNode(
+                this.statement_block_1.inputList[0]));
+      });
+      test('Cursor on block inside statement', function() {
+        Blockly.navigation.cursor_.setLocation(
+            Blockly.ASTNode.createConnectionNode(
+                this.stack_block_2.previousConnection));
+        chai.assert.isTrue(Blockly.navigation.modify_());
+        chai.assert.equal(this.stack_block_2.previousConnection.targetBlock(),
+            this.statement_block_1);
+      });
+      test('Cursor on stack', function() {
+        Blockly.navigation.cursor_.setLocation(
+            Blockly.ASTNode.createStackNode(
+                this.statement_block_2));
+        chai.assert.isTrue(Blockly.navigation.modify_());
+        chai.assert.equal(this.statement_block_2.getParent().id, 'statement_block_1');
+      });
+      test('Cursor on incompatible type', function() {
+        Blockly.navigation.cursor_.setLocation(
+            Blockly.ASTNode.createConnectionNode(
+                this.row_block_1.outputConnection));
+        chai.assert.isFalse(Blockly.navigation.modify_());
+        chai.assert.equal(this.row_block_1.getParent(), null);
+      });
+
     });
 
     suite('Marker on output', function() {
@@ -171,26 +205,26 @@ suite('Insert/Modify', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createConnectionNode(
                 this.row_block_2.inputList[0].connection));
-        chai.assert.isTrue(Blockly.navigation.modify());
+        chai.assert.isTrue(Blockly.navigation.modify_());
         chai.assert.equal(this.row_block_1.getParent().id, 'row_block_2');
       });
       test('Cursor on incompatible connection', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createConnectionNode(
                 this.row_block_2.outputConnection));
-        chai.assert.isFalse(Blockly.navigation.modify());
+        chai.assert.isFalse(Blockly.navigation.modify_());
       });
       test('Cursor on really incompatible connection', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createConnectionNode(
                 this.stack_block_1.previousConnection));
-        chai.assert.isFalse(Blockly.navigation.modify());
+        chai.assert.isFalse(Blockly.navigation.modify_());
       });
       test('Cursor on block', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createBlockNode(
                 this.row_block_2));
-        chai.assert.isTrue(Blockly.navigation.modify());
+        chai.assert.isTrue(Blockly.navigation.modify_());
         chai.assert.equal(this.row_block_1.getParent().id, 'row_block_2');
       });
     });
@@ -207,7 +241,7 @@ suite('Insert/Modify', function() {
       Blockly.navigation.cursor_.setLocation(
           Blockly.ASTNode.createBlockNode(
               this.row_block_1));
-      chai.assert.isTrue(Blockly.navigation.modify());
+      chai.assert.isTrue(Blockly.navigation.modify_());
       var pos = this.row_block_1.getRelativeToSurfaceXY();
       chai.assert.equal(100, pos.x);
       chai.assert.equal(200, pos.y);
@@ -217,7 +251,7 @@ suite('Insert/Modify', function() {
       Blockly.navigation.cursor_.setLocation(
           Blockly.ASTNode.createConnectionNode(
               this.row_block_1.outputConnection));
-      chai.assert.isTrue(Blockly.navigation.modify());
+      chai.assert.isTrue(Blockly.navigation.modify_());
       var pos = this.row_block_1.getRelativeToSurfaceXY();
       chai.assert.equal(100, pos.x);
       chai.assert.equal(200, pos.y);
@@ -227,7 +261,7 @@ suite('Insert/Modify', function() {
       Blockly.navigation.cursor_.setLocation(
           Blockly.ASTNode.createConnectionNode(
               this.stack_block_1.previousConnection));
-      chai.assert.isTrue(Blockly.navigation.modify());
+      chai.assert.isTrue(Blockly.navigation.modify_());
       var pos = this.stack_block_1.getRelativeToSurfaceXY();
       chai.assert.equal(100, pos.x);
       chai.assert.equal(200, pos.y);
@@ -237,14 +271,16 @@ suite('Insert/Modify', function() {
       Blockly.navigation.cursor_.setLocation(
           Blockly.ASTNode.createConnectionNode(
               this.row_block_1.inputList[0].connection));
-      chai.assert.isFalse(Blockly.navigation.modify());
+      // Move the source block to the marked location on the workspace.
+      chai.assert.isTrue(Blockly.navigation.modify_());
     });
 
     test('Cursor on next connection', function() {
       Blockly.navigation.cursor_.setLocation(
           Blockly.ASTNode.createConnectionNode(
               this.stack_block_1.nextConnection));
-      chai.assert.isFalse(Blockly.navigation.modify());
+      // Move the source block to the marked location on the workspace.
+      chai.assert.isTrue(Blockly.navigation.modify_());
     });
 
     test('Cursor on child block (row)', function() {
@@ -255,7 +291,7 @@ suite('Insert/Modify', function() {
           Blockly.ASTNode.createBlockNode(
               this.row_block_2));
 
-      chai.assert.isTrue(Blockly.navigation.modify());
+      chai.assert.isTrue(Blockly.navigation.modify_());
       chai.assert.isNull(this.row_block_2.getParent());
       var pos = this.row_block_2.getRelativeToSurfaceXY();
       chai.assert.equal(100, pos.x);
@@ -270,7 +306,7 @@ suite('Insert/Modify', function() {
           Blockly.ASTNode.createBlockNode(
               this.stack_block_2));
 
-      chai.assert.isTrue(Blockly.navigation.modify());
+      chai.assert.isTrue(Blockly.navigation.modify_());
       chai.assert.isNull(this.stack_block_2.getParent());
       var pos = this.stack_block_2.getRelativeToSurfaceXY();
       chai.assert.equal(100, pos.x);
@@ -281,7 +317,7 @@ suite('Insert/Modify', function() {
       Blockly.navigation.cursor_.setLocation(
           Blockly.ASTNode.createWorkspaceNode(
               this.workspace, new Blockly.utils.Coordinate(100, 100)));
-      chai.assert.isFalse(Blockly.navigation.modify());
+      chai.assert.isFalse(Blockly.navigation.modify_());
     });
   });
 
@@ -300,7 +336,7 @@ suite('Insert/Modify', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createWorkspaceNode(
                 this.workspace, new Blockly.utils.Coordinate(100, 100)));
-        chai.assert.isFalse(Blockly.navigation.modify());
+        chai.assert.isFalse(Blockly.navigation.modify_());
 
       });
     });
@@ -314,25 +350,25 @@ suite('Insert/Modify', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createBlockNode(
                 this.row_block_1));
-        chai.assert.isFalse(Blockly.navigation.modify());
+        chai.assert.isFalse(Blockly.navigation.modify_());
       });
       test('Cursor on stack block', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createBlockNode(
                 this.stack_block_1));
-        chai.assert.isFalse(Blockly.navigation.modify());
+        chai.assert.isFalse(Blockly.navigation.modify_());
       });
       test('Cursor on next connection', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createConnectionNode(
                 this.stack_block_2.nextConnection));
-        chai.assert.isFalse(Blockly.navigation.modify());
+        chai.assert.isFalse(Blockly.navigation.modify_());
       });
       test('Cursor on previous connection', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createConnectionNode(
                 this.stack_block_2.previousConnection));
-        chai.assert.isFalse(Blockly.navigation.modify());
+        chai.assert.isFalse(Blockly.navigation.modify_());
       });
     });
     suite('Marked row block', function() {
@@ -345,25 +381,25 @@ suite('Insert/Modify', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createBlockNode(
                 this.stack_block_1));
-        chai.assert.isFalse(Blockly.navigation.modify());
+        chai.assert.isFalse(Blockly.navigation.modify_());
       });
       test('Cursor on row block', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createBlockNode(
                 this.row_block_1));
-        chai.assert.isFalse(Blockly.navigation.modify());
+        chai.assert.isFalse(Blockly.navigation.modify_());
       });
       test('Cursor on value input connection', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createConnectionNode(
                 this.row_block_2.inputList[0].connection));
-        chai.assert.isFalse(Blockly.navigation.modify());
+        chai.assert.isFalse(Blockly.navigation.modify_());
       });
       test('Cursor on output connection', function() {
         Blockly.navigation.cursor_.setLocation(
             Blockly.ASTNode.createConnectionNode(
                 this.row_block_2.outputConnection));
-        chai.assert.isFalse(Blockly.navigation.modify());
+        chai.assert.isFalse(Blockly.navigation.modify_());
       });
     });
   });
diff --git a/tests/mocha/navigation_test.js b/tests/mocha/navigation_test.js
index 654eb9d33..bead4fa50 100644
--- a/tests/mocha/navigation_test.js
+++ b/tests/mocha/navigation_test.js
@@ -282,13 +282,13 @@ suite('Navigation', function() {
     });
 
     test('Insert', function() {
-      sinon.spy(Blockly.navigation, 'modify');
+      sinon.spy(Blockly.navigation, 'modify_');
       this.mockEvent.keyCode = Blockly.utils.KeyCodes.I;
       chai.assert.isTrue(Blockly.navigation.onKeyPress(this.mockEvent));
-      chai.assert.isTrue(Blockly.navigation.modify.calledOnce);
+      chai.assert.isTrue(Blockly.navigation.modify_.calledOnce);
       chai.assert.equal(Blockly.navigation.currentState_,
           Blockly.navigation.STATE_WS);
-      Blockly.navigation.modify.restore();
+      Blockly.navigation.modify_.restore();
     });
 
     test('Mark', function() {
@@ -504,7 +504,7 @@ suite('Navigation', function() {
       var sourceNode = Blockly.ASTNode.createConnectionNode(this.basicBlock2.nextConnection);
       Blockly.navigation.cursor_.setLocation(sourceNode);
 
-      Blockly.navigation.modify();
+      Blockly.navigation.modify_();
       var insertedBlock = this.basicBlock.previousConnection.targetBlock();
 
       chai.assert.isNotNull(insertedBlock);
@@ -673,5 +673,16 @@ suite('Navigation', function() {
       chai.assert.equal(this.workspace.cursor.getCurNode().getType(),
           Blockly.ASTNode.types.WORKSPACE);
     });
+
+    test('Delete top block in stack', function() {
+      this.basicBlockA.nextConnection.connect(this.basicBlockB.previousConnection);
+      var astNode = Blockly.ASTNode.createStackNode(this.basicBlockA);
+      // Set the cursor to be on the stack
+      this.workspace.cursor.setLocation(astNode);
+      // Remove the top block in the stack
+      this.basicBlockA.dispose();
+      chai.assert.equal(this.workspace.cursor.getCurNode().getType(),
+          Blockly.ASTNode.types.WORKSPACE);
+    });
   });
 });
diff --git a/tests/mocha/test_helpers.js b/tests/mocha/test_helpers.js
index 3a44579e9..022e7eadd 100644
--- a/tests/mocha/test_helpers.js
+++ b/tests/mocha/test_helpers.js
@@ -1,7 +1,7 @@
 /* exported assertEquals, assertNotEquals, assertArrayEquals, assertTrue, assertFalse,
    assertNull, assertNotNull, assertNotNullNorUndefined, assert,
    isEqualArrays, assertUndefined, assertNotUndefined,
-   defineRowBlock, defineStackBlock */
+   defineRowBlock, defineStackBlock, defineStatementBlock */
 function _argumentsIncludeComments(expectedNumberOfNonCommentArgs, args) {
   return args.length == expectedNumberOfNonCommentArgs + 1;
 }
@@ -158,3 +158,21 @@ function defineRowBlock() {
   }]);
 }
 
+function defineStatementBlock() {
+  Blockly.defineBlocksWithJsonArray([{
+    "type": "statement_block",
+    "message0": "%1",
+    "args0": [
+      {
+        "type": "input_statement",
+        "name": "NAME"
+      }
+    ],
+    "previousStatement": null,
+    "nextStatement": null,
+    "colour": 230,
+    "tooltip": "",
+    "helpUrl": ""
+  }]);
+}
+