diff --git a/blocks/logic.js b/blocks/logic.js
index 8846b7141..245589513 100644
--- a/blocks/logic.js
+++ b/blocks/logic.js
@@ -427,5 +427,36 @@ Blockly.Blocks['logic_ternary'] = {
         .appendField(Blockly.Msg.LOGIC_TERNARY_IF_FALSE);
     this.setOutput(true);
     this.setTooltip(Blockly.Msg.LOGIC_TERNARY_TOOLTIP);
+    this.prevParentConnection_ = null;
+  },
+  /**
+   * Called whenever anything on the workspace changes.
+   * Prevent mismatched types.
+   * @this Blockly.Block
+   */
+  onchange: function() {
+    if (!this.workspace) {
+      // Block has been deleted.
+      return;
+    }
+    var blockA = this.getInputTargetBlock('THEN');
+    var blockB = this.getInputTargetBlock('ELSE');
+    var parentConnection = this.outputConnection.targetConnection;
+    // Kick blocks that existed prior to this change if they don't match.
+    if ((blockA || blockB) && parentConnection) {
+      for (var i = 0; i < 2; i++) {
+        var block = (i == 1) ? blockA : blockB;
+        if (block && !block.outputConnection.checkType_(parentConnection)) {
+          if (parentConnection === this.prevParentConnection_) {
+            this.setParent(null);
+            parentConnection.sourceBlock_.bumpNeighbours_();
+          } else {
+            block.setParent(null);
+            block.bumpNeighbours_();
+          }
+        }
+      }
+    }
+    this.prevParentConnection_ = parentConnection;
   }
 };
diff --git a/blocks_compressed.js b/blocks_compressed.js
index cb161591c..05ae113ab 100644
--- a/blocks_compressed.js
+++ b/blocks_compressed.js
@@ -53,7 +53,8 @@ Blockly.Blocks.logic_operation={init:function(){var a=[[Blockly.Msg.LOGIC_OPERAT
 OR:Blockly.Msg.LOGIC_OPERATION_TOOLTIP_OR}[a]})}};Blockly.Blocks.logic_negate={init:function(){this.setHelpUrl(Blockly.Msg.LOGIC_NEGATE_HELPURL);this.setColour(Blockly.Blocks.logic.HUE);this.setOutput(!0,"Boolean");this.interpolateMsg(Blockly.Msg.LOGIC_NEGATE_TITLE,["BOOL","Boolean",Blockly.ALIGN_RIGHT],Blockly.ALIGN_RIGHT);this.setTooltip(Blockly.Msg.LOGIC_NEGATE_TOOLTIP)}};
 Blockly.Blocks.logic_boolean={init:function(){var a=[[Blockly.Msg.LOGIC_BOOLEAN_TRUE,"TRUE"],[Blockly.Msg.LOGIC_BOOLEAN_FALSE,"FALSE"]];this.setHelpUrl(Blockly.Msg.LOGIC_BOOLEAN_HELPURL);this.setColour(Blockly.Blocks.logic.HUE);this.setOutput(!0,"Boolean");this.appendDummyInput().appendField(new Blockly.FieldDropdown(a),"BOOL");this.setTooltip(Blockly.Msg.LOGIC_BOOLEAN_TOOLTIP)}};
 Blockly.Blocks.logic_null={init:function(){this.setHelpUrl(Blockly.Msg.LOGIC_NULL_HELPURL);this.setColour(Blockly.Blocks.logic.HUE);this.setOutput(!0);this.appendDummyInput().appendField(Blockly.Msg.LOGIC_NULL);this.setTooltip(Blockly.Msg.LOGIC_NULL_TOOLTIP)}};
-Blockly.Blocks.logic_ternary={init:function(){this.setHelpUrl(Blockly.Msg.LOGIC_TERNARY_HELPURL);this.setColour(Blockly.Blocks.logic.HUE);this.appendValueInput("IF").setCheck("Boolean").appendField(Blockly.Msg.LOGIC_TERNARY_CONDITION);this.appendValueInput("THEN").appendField(Blockly.Msg.LOGIC_TERNARY_IF_TRUE);this.appendValueInput("ELSE").appendField(Blockly.Msg.LOGIC_TERNARY_IF_FALSE);this.setOutput(!0);this.setTooltip(Blockly.Msg.LOGIC_TERNARY_TOOLTIP)}};
+Blockly.Blocks.logic_ternary={init:function(){this.setHelpUrl(Blockly.Msg.LOGIC_TERNARY_HELPURL);this.setColour(Blockly.Blocks.logic.HUE);this.appendValueInput("IF").setCheck("Boolean").appendField(Blockly.Msg.LOGIC_TERNARY_CONDITION);this.appendValueInput("THEN").appendField(Blockly.Msg.LOGIC_TERNARY_IF_TRUE);this.appendValueInput("ELSE").appendField(Blockly.Msg.LOGIC_TERNARY_IF_FALSE);this.setOutput(!0);this.setTooltip(Blockly.Msg.LOGIC_TERNARY_TOOLTIP);this.prevParentConnection_=null},onchange:function(){if(this.workspace){var a=
+this.getInputTargetBlock("THEN"),b=this.getInputTargetBlock("ELSE"),c=this.outputConnection.targetConnection;if((a||b)&&c)for(var d=0;2>d;d++){var e=1==d?a:b;e&&!e.outputConnection.checkType_(c)&&(c===this.prevParentConnection_?(this.setParent(null),c.sourceBlock_.bumpNeighbours_()):(e.setParent(null),e.bumpNeighbours_()))}this.prevParentConnection_=c}}};
 // Copyright 2012 Google Inc.  Apache License 2.0
 Blockly.Blocks.loops={};Blockly.Blocks.loops.HUE=120;
 Blockly.Blocks.controls_repeat={init:function(){this.setHelpUrl(Blockly.Msg.CONTROLS_REPEAT_HELPURL);this.setColour(Blockly.Blocks.loops.HUE);this.appendDummyInput().appendField(Blockly.Msg.CONTROLS_REPEAT_TITLE_REPEAT).appendField(new Blockly.FieldTextInput("10",Blockly.FieldTextInput.nonnegativeIntegerValidator),"TIMES").appendField(Blockly.Msg.CONTROLS_REPEAT_TITLE_TIMES);this.appendStatementInput("DO").appendField(Blockly.Msg.CONTROLS_REPEAT_INPUT_DO);this.setPreviousStatement(!0);this.setNextStatement(!0);