When I type in an address, half way through it switches down the Google window, then if I go back up to the address section, the whole thing becomes highlighted and erases what I have already typed. Very annoying.

Question

The details are in the "question" above. It's really more like a statement.

Answer 1

I am not sure if the switch tab feature can be turned off. I did initially find it a minor irritation, but it does have the advantage if tabs scroll off screen that you are made aware of existing matching tabs, so I have come to see it as an improvement.
I have just tried with firefox4 to make sure and I am able to easily open multiple same tabs by for instance using '''Firefoxbutton -> history'''
There is along discussion thread in [http://forums.mozillazine.org/viewtopic.php?f=23&t=1977593&start=45 Mozilazine] about this feature and how it interacts with auto-fill.
You can of course use the (windows) '''right click option''' from links on a webpage to open other related pages in a new tab.
Also from the search bar or the location bar '''Alt + Enter''' will open that address in a new tab. And''' Control and drag''' with mouse on the tab will duplicate it.