[Novice Problem] With CharacterFormat

Hi everybody,

I am working with TLF for few days and I don't understand something...
I have created a textflow, and I want to apply a style (color, fontFamily...) on selected characters

But when I use CharacterFormat, the style is applied on all the text.

My first try (juste change the colortext) :
Here I create my textflow :

private var _textFlow:TextFlow = null;
                private var _container:Sprite = null;
                public var manager:EditManager;

private function initNote():void
                {
                        var controller:IContainerController;
                
                        _container = new Sprite();
                        textArea.rawChildren.addChild(_container);
                        _textFlow = new TextFlow ();
                        
                        controller = new DisplayObjectContainerController(_container,textArea.width,textArea.height);
                        _textFlow.flowComposer.addController(controller);

                        _textFlow.addEventListener(StatusChangeEvent.INLINE_GRAPHIC_STATUS_CHANGED, graphicStatusChangeEvent);
                        
                        manager = new EditManager(new UndoManager());
                        _textFlow.interactionManager = manager;
                        
                        _textFlow.interactionManager.setSelection(0,0);
                        
                        _textFlow.flowComposer.updateAllContainers();
                        _textFlow.interactionManager.setFocus();
                }
                

Here, I want to apply the selected color

private function changeCharacterColor(event:ColorPickerEvent😞void
{
                        var cf:CharacterFormat = new CharacterFormat(currentNote.myTextFlow.characterFormat);
                        
                        cf.color = colorChar.value;
                        currentNote.myTextFlow.characterFormat = cf;
                        currentNote.myTextFlow.flowComposer.updateAllContainers();
                }

I checked  the selection to be sure that it is good (thanks to the TextScrap options). But no problem on this side.

I try today with myTextFlow.interactionManager.selectionState.pointFormat = cf to apply the new color. But it doesn't work too.

I think I have miss something. Can somebody help me?

Thank you very much.

NB: Sorry for my bad english 😕😕 (poor french I am )