Another interesting "mouse behavior" irony

After posting the comedy of dust in an optical mouse a while ago, I have gotten into the habit of blowing it out when the mouse acts strange. Today, it happened again; but blowing it out did nothing, so I physically cleaned it out and immediately saw the desktop icons change size! (I am glad I left it powered on when cleaning, or I would never have figured this out.)
 
Only the Ctrl key does this... so I immediately popped the left-ctrl key out (wow the crap under those keys!), cleaned it out, and popped it back in. Checked it quickly for smooth operation and went merrily on my way.
 
Bottom line, the left-Ctrl key was the issue... it wasn't always releasing fully and sending spurious data that only "showed up" in the mouse movement.
 
Just wanted to throw this out, since a lot of "odd system behavior" gets resolved with some of the stupidest things.