Winston, that's an effect of my tweaks. That particular setting stores two states. The page you are currently on and the page you came from. The reasoning is that doing so saves memory because the browser is not holding more than two pages in memory.
Here is the setting to change that: browser.sessionhistory.max_entries
Go into about:config and find that setting. Double click on the number (should be 2 as that is my setting) and change it to reflect the number of pages back you want to store. I believe the default is 100 (or something like that).
Welcome to MacRumors, by the way!
Ah! That makes sense. I really appreciate the detailed response. Do you know if this helps with the memory leaks I seem to get with TenFourFox? I've gotten to where I regularly quit the program to free up memory, then restart it.
Thanks again.
- Winston