Sometimes when you hit back in firefox, it takes you to the top of the page and not 
where you were last browsing. To change this, do the following:

1. Open a new tab in Firefox (Ctrl t)
2. In the address bar type about:config
3. This will bring up a prefrences panel, type in the filter bar at the top:

browser.cache.check_doc_frequency

4. Double click on browser.cache.check_doc_frequency
5. A box should apear that says Enter integer value
6. Default for this setting is 3
7. Change it to 1
8. Click Ok
9. Close Firefox and restart it and the settings will take effect.

This will stop the page from doing a complete reload everytime you hit back.