I can’t tell for sure because the video doesn’t show the very bottom of the Lectora window, but it seems like you’ve positioned the top of the Action Pane to its lowest point. At its lowest point, the only thing visible is the 5 pixel top border of the pane. You can tell the Action Pane is “visible” in your video because when you click on the action in the Title Explorer, the Action Pane button on the ribbon is already highlighted. Then when you click the Action Pane button (to hide the pane), the top of the page view drops by about 5 pixels because the Action Pane was hidden. Then when you click the Action Pane button again (to show the pane), the top of the page view goes up by about 5 pixels and you get the flash because the Action Pane was shown. My title reacts exactly the same when I do this. If this is the case with your title then you just have to reposition the top of the Action Pane by grabbing it and dragging it up.