Click on the button - look at the properties tab - make certain that 'link' is set to the timeline that plays the full movie.
Or if you already have a button that does that and you just want this extra button you described in your post to go away - Select the button - Edit - Clear
Or if you don't want any buttons at all - select the dvd icon in the flow chart and set the full movie timeline to be first play in the properties tab.