Lately, for some reason, my dock has become very glitchy. It randomely turns completely transparent and leaves only the icons and their reflections viewable. Even the effects of the stacks are lost, the "fan" effect in particular. When clicked, nothing shows up! The only way I know how to fix all of this is to do a restart. I've attached two pictures, the first shows the glitched dock while the second shows me clicking on my Applications stack. What's the problem here, and is there a way to prevent this?