Getting a runtime error in TextContainerManager.as

Using Adoeb AIR 2.7 & Flex SDK 4.5.1.21328 & TLF 2.1

The error is thrown on line 2425: (TextContainerManager.as)

parent value is null

tlf_internal function removeInlineGraphicElement(parent:DisplayObjectContainer, inlineGraphicElement:DisplayObject):void
          {
               if (inlineGraphicElement.parent == parent)
                    parent.removeChild(inlineGraphicElement);
          }

Here is the error:

TypeError: Error #1009: Cannot access a property or method of a null object reference.
     at flashx.textLayout.container::TextContainerManager/http://ns.adobe.com/textLayout/internal/2008::removeInlineGraphicElement()

Reproduce step.

1. AddImage button click. And select any image.

2. Add two or three images.

3. After moving the cursor to the end.

4. 5-6 times press enter.

5. The scroll bar is displayed, press Enter several times an error occurs.

Here is the full source code:

<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009" 
                            xmlns:s="library://ns.adobe.com/flex/spark" 
                            xmlns:mx="library://ns.adobe.com/flex/mx" width="400" height="500">
     <fx:Declarations>
          <!-- Place non-visual elements (e.g., services, value objects) here -->
     </fx:Declarations>
     <s:layout>
          <s:VerticalLayout gap="0" horizontalAlign="center"/>
     </s:layout>
     <fx:Script>
          <![CDATA[
               import flashx.textLayout.edit.EditManager;
               
               private function addImage(event:MouseEvent):void
               {
                    var em:EditManager = editor.textFlow.interactionManager as EditManager;
                    em.selectRange(editor.selectionAnchorPosition, editor.selectionActivePosition);
                    editor.setFocus();
                    
                    var file:File = new File();
                    var imagesFilter:FileFilter = new FileFilter('Images', '*.jpg;*.gif;*.png');
                    file.addEventListener(Event.SELECT, onSelectedImage);
                    file.browseForOpen('Select Image', [imagesFilter]);
               }
               
               private function onSelectedImage(event:Event):void
               {
                    var file:File = event.target as File;
                    var em:EditManager = editor.textFlow.interactionManager as EditManager;
                    em.selectRange(editor.selectionAnchorPosition, editor.selectionActivePosition);
                    editor.setFocus();
                    
                    em.selectRange(editor.selectionAnchorPosition, editor.selectionActivePosition);
                    em.insertText('\n');
                    em.insertInlineGraphic(file.nativePath,200,200);
                    editor.textFlow.flowComposer.updateAllControllers();
                    editor.setFocus();
               }
               
     ]]>
     </fx:Script>
     <s:TextArea id="editor" width="100%" height="100%" lineHeight="102%" />
     <s:Button id="addImgBtn" label="AddImage" click="addImage(event)" />
</s:WindowedApplication>
 

Please check.

Thanks.