Timing bulleted list with narration

Hello Heroes, I am building a course with SL and want the text on the slides to time with my narration. About an hour ago, after selecting one of my text boxes on a slide, I pressed the right arrow key by mistake. When I looked at my timeline, something looked different and at first I thought the selected text box disappeared. But what I discovered was the text box was now split up into layers, and each bulleted item had its own layer that I could easily move to time precisely with the narration. I tried this "mistake" again (pressing right arrow) on another text box with a bulleted list and the same thing happened. I did this a couple more times. I thought I discovered a feature of SL by accident and considering how easy it was, I was thrilled. HOWEVER, now the technique is not working! When I select a text box in the timeline and press the right arrow key, all that happens is the text box slides a bit to the right on the timeline. I feel like I'm loosing my mind. I searched the forums and could not find an answer... does anyone know? I've attached a screen shot of my timeline where this did work (circled in red). I want to be able to keep doing this with lists. Its much easier than creating a new text box for every list item that I want to control. I hope my question makes sense. Thanks!