Author-it Presentations are designed to display at a resolution of 1024 x 768, which is the resolution used by 99 per cent of projectors. For best results, view presentations using this resolution. Most projectors will not display the slides correctly at resolutions higher than 1024 x 768.
However, if your monitor is set at a resolution higher than 1024 x 768 the frameset resizes to fill the screen and can appear to be broken into separate frames. When you use a higher resolution, the slide is anchored to the top left corner of the main frame and displays a black background around the right and lower sides, similar to the image below. The TOC frame still displays at the right of the screen, and the Control frame at the bottom of the screen.