De-shadow blocks that have been edited.

core/field_textinput.js

@@ -195,6 +195,7 @@ Blockly.FieldTextInput.prototype.onHtmlInputChange_ = function(e) {
     // Update source block.
     var text = htmlInput.value;
     if (text !== htmlInput.oldValue_) {
+      this.sourceBlock_.setShadow(false);
       htmlInput.oldValue_ = text;
       this.setText(text);
       this.validate_();