In PowerPoint, you have to option to display drawing guides that help you align objects on a slide. A common application is to have some sort of frame around your slide to make sure that you have the same margin around all your slides in a presentation.
I find these frames very useful, but there is a small issue you need to watch out for, when making compositions, my brain actually assumes that the dotted lines are part of the slide, and I start positioning objects accordingly. When you switch of the frames, or look at the slide in presentation mode, the whole balance looks wrong somehow.
So: always check your slide compositions with those drawing guides disabled.
PS. In my presentation design app SlideMagic, there is no need for drawing guides, since you are forced (kindly), to use a predetermined grid. Try it out!