It it usually the OS that does the window tiling if a window is created at the same position on the screen and not Firefox, so there is not much to do about this.

It has nothing to do with the OS. IE doesn't behave that way. Aplications that remember their Window position when the window is closed (FireFox included) and start up in the same position when the first app window is opened again do not suddenly get put someplace else by the OS.

When I asked my IT support person (who uses Firefox exclusively) I was told this is specifically a FireFox "feature."

The only workaround I see is to click the Maximize window button in the top right corner. Close Firefox to save this setting. Reopen Firefox then try to open a new window. It should now completely cover your previous window everytime you open a new window.

That doesn't help. I don't want the browser occupying the whole screen or I wouldn't care so much if later windows were positioned lower. A reason I don't want the new windows to appear lower on the screen is that I want to see stuff on the bottom part of the screen with the browser window extending down 80% of the way from the top of the screen leaving room for other stuff to be visible at the bottom.

You should begin to prepare to upgrade to Firefox 11. Firefox 3.6 will be dropped from support in a few weeks, which means it will no longer be receiving security or stability updates. Firefox 11 is up to 7 times faster than 3.6, has lots of new features and improvements, as well as support for new web standards. http://www.mozilla.org/en-US/firefox/features/ and Updating Firefox have more information.

Also, try updating Windows to the latest version (all service packs, updates, etc.) and update your graphics driver (Firefox uses your graphics card for some rendering, and an out of date graphics card driver can cause problems. https://support.mozilla.org/en-US/kb/how-do-i-upgrade-my-graphics-drivers.

Update all your plugins (Flash, Java, etc.): http://www.mozilla.org/plugincheck/.

If I upgrade to Firefox 11 will I have control over (and be able to turn off) this "feature?"

This isn't a"feature" persay. I'm wondering if it is a bug however. With Firefox 3.6.6, you are open to so many security holes it isn't even funny. Plus Firefox 3.6 is being dropped from support in just a few weeks.

Is there a specific reason you prefer to open a new window, instead of a tab? It sounds like you'd love the tab groups feature. You can learn about it and even check out a video about it in the Use Tab Groups to organize a lot of tabs article.

I asked you guys not to ask WHY since that's not really relevant to the question.

But since you did here are the answers:

First: I am a committed keyboard user. The shortcut for switching between top level windows is Alt-Tab and I can do that with two fingers on one hand quite quickly, quite effectively, and quite comfortably. So my usual methodology when browsing certain web sites where I want to see lots of pages is SHIFT-CLICK on the link and immediately ALT-TAB back to the window I was looking at so I can continue reading and finding the next link I am interested in. I put my thumb on the ALT-KEY and press TAB with my ring finger. My hand rests naturally on the keyboard. The same finger that operates the TAB key moves easily down to the SHIFT key when needed to open a new link.

To use the CTRL-TAB sequence to move between tabs means I have to rotate my elbow away from my body and twist my hand to get the thumb on the CTRL key. This is very uncomfortable.

To use the CTRL-PGDN or CTRL-PGUP I have to take my right hand off the mouse. I find this motion very inefficient. I work much faster with the one hand on the keyboard an the other on the mouse.

Could there be some alternate key combination as convenient as ALT-TAB? Maybe, (unlikely, but maybe) but I am sure using two different key combinations in two different apps would have me making mistakes sooner or later. ALT-TAB fist my fingers very well. The UI developer who picked that combo was very smart.

I realize some of this may be quite incomprehensible to people who are mouse-centric. But I get a lot done much faster with the keyboard than anyone else I have seen attempting to do the equivalent tasks with only a mouse.

Second Reason: I don't always want to close the windows in the exact reverse order I open them. With IE positioning the windows one on top of another, it doesn't make any difference what order I close the windows. When I start the browser again, the window is still where I want it (full screen width, at the very top, with 1/5 of the screen at the bottom available to look at other stuff).

With Firefox positioning new windows one titlebar height down, if do not close the windows in the exact opposite order I opened them, the last position that Firefox remembers is further down on the screen. When I re-open Firefox, the windows is not where I want it to be.

I did some research and concocted a script I put in a local file/page I call "To-The-Top" that repositions the window for the times I make a mistake and don't close windows in the right order. I just don't think this should be necessary. BTW, I am a professional programmer so not only do I not _think_ this should not be necessary, I _know_ it is not necessary if I could find out how to turn off this "feature."

Does that help?