OS X Yosemite :: Browser Disappeared To Right

I recently upgraded to Mac Yosemite...30min ago, I was on the Chrome browser and happened to throw the browser to the right. Fyi, I'm not using mighty mouse and have only 1 monitor. When I tried to bring it back to the center, I couldn't find it in anywhere on the right side of the monitor. It was gone.

But in the dock, chrome was showing that it's up and running just fine. I was also able to see that all the tabs were still open.  Thinking it's some glitch, I restarted the computer but when I clicked on Chrome, the issue remained same. And even after uninstalled, reinstalled Chrome!I can see the top menu (as in the attached pics, the open browser is firefox) but browser doesn't appear at all.

No matter what I try so far, it just doesn't work. I can also click on those top menu, such as preference or history, but no window would pop up.   

First I thought it was Chrome issue. But when I tried moving Firefox to the right, but hoping it at the edge of the right side of the screen, firefox was also about to disappear. The browser became very transparent. Because I still had Safari to use, I let go of the browser when it turned super transparent, then pshhhhhht! It's gone, too. Now firefox is showing the exactly same symptoms: open in the dock and the top menu but no browser, etc. 

Info:
Mac Pro, OS X Yosemite (10.10.1)