- Turn off the annoying splash screen, which will make FF start up slightly faster [edit: it doesn't make it faster] (this is described below).
- Found a way today to customize multiple copies of Firefox multiple different ways and run them simultaneously. There are several reasons for running multiple browsers at the same time:
- Different add-ons (or groups of add-ons) can almost create an entirely new browser. You may want to keep your old one.
- The great add-on "Noscript" even when disabled, can break some websites. Having a second browser available can get around this problem.
- When you want one browser with "Private Browsing" and one without, great for testing.
Running multiple instances of Firefox
This is explained here but I'll post a short version:
- Download and extract Firefox Portable
- Open the text file FirefoxPortable\Other\Source\FirefoxPortable.ini
- Edit the lines "DisableSplashScreen" and "AllowMultipleInstances" and change "false" to "true" on both lines. Save changes.
- Copy the text file into the same directory as PortableFirefox.exe (FirefoxPortable\FirefoxPortable.ini)
- Copy the entire FirefoxPortable directory to a separate directory (e.g. FirefoxPortable2)
NOTE: getting multiple profiles in Portable Firefox (and Thunderbird) is discussed here.