The Mystery Of The Disappearing App Icons

If I try to rearrange the shortcuts to app icons on my homescreen, sometimes they disappear. It happens to all apps, bookmarks, and folders, too: even stock apps, like Play Store. I have an LG optimus s that I got about a year ago, new. I'm running 2.3.3. Gingerbread. Details : app icons often reappear in folders after reboot, sometimes without reboot. I'll say again, for clarity, that this only happens when I attempt to rearrange the icons : no spontaneous disappearances! I use my phone almost 24/7, as I do not own a tablet or a computer with wifi, so I like everything to be in it's place.