QUESTION: My “Show Desktop” icon just disappeared from my Quick Start menu. How do I restore that?
ANSWER: It probably got “bumped” aside by something else putting an icon in that space. You can drag that double greater than (>%gt;) sign and make that space wider.
OR just temporarily expand that space and drag and drop that Show Desktop icon to the far left where I personally like to keep mine.
If that doesn't fix it, go here.