Tabs can be moved to the left or right or pulled off in Chrome by using the mouse. The tab pull-off behavior in Windows is pretty solid. On Ubuntu however, I find that it is too sensitive. Many a time, when I try to move a tab to the left or right, Chrome recognizes this operation as a tab pull-off and proceeds to pull it off into a new window. This is highly irritating!
If this happens to you, you can undo this operation. But to do that, you should not have yet lifted the left mouse click. If you have the left mouse button still depressed and the tab has been pulled off, just press Esc with your other hand. Do this without letting go of the mouse button. The tab will snap back to the Chrome window and all is well.
Tried with: Chrome 24.0.1312.68 and Ubuntu 12.04 LTS