I'm just blogging this as I would never have been able to Google this. Luckily I've got a smart (freaky) friend who seems to have a wealth of knowledge for these things.
So yesterday I hooked up my new monitor, a 30 inch LCD from Dell. Yes, 30 inches. Insane. I don't know what I was thinking (tax reduction!) but I'm now staring at a giant screen. My Mac wasn't powerful enough to drive both the 30 and 24 inch, so I kept my old 18 inch Sony to the right.
Everything was hunky dorey but I noticed an odd issue with my mouse. I'd move it to the right, and sometimes it would get stuck. I'd shake it back and forth a few times and then finally it would enter the right monitor.
Turns out the issue was with the placement of my monitors in the display preferences. Check out this screen shot:
Notice that the right monitor, being smaller, doesn't stretch all the way to the top. That means if the mouse is on top of the left monitor, it won't be able to move over. To move my mouse into the secondary monitor, I need to keep it lower. (I actually had the placement on top first, but find this bottom aligned setup easier, and it visually matches what I see in front of me.)
So again - just sharing the tip in hopes it helps someone else in the future. (Quote: When did we go from writing for posterity to writing for Google?)