1. Performance
Disable the session restore on crash
browser.sessionstore.resume_from_crash -> false
Reduce memory usage by reducing images store time in the memory
image.mem.min_discard_timeout_ms -> < 10000
Images cache maximum capacity
browser.cache.memory.capacity -> ~5000 (KB)
Max pages to store in memory for Back/Forward buttons
browser.sessionhistory.max_total_viewers -> 3
Disable/enable image loading
permissions.default.image -> [0]: always; [1]: never; [2]: don't load third party images
2. Interface
Turn off the “Downloads Complete” alert
browser.download.manager.showAlertOnComplete -> false
Close multiple tabs without warning
browser.tabs.warnOnCloseOtherTabs -> false
Show separate Downloads window [F29+]
browser.download.useToolkitUI
If not working use the Downloads Window extension
Classic search bar [F29+]
browser.search.showOneOffButtons -> false
Disable tabs animation on open/close [F29+]
browser.tabs.animate -> false
Disable Close button in tab
browser.tabs.closebuttons -> false
For Firefox 29+ use “No Close Buttons” extension
3. Selection
Change selection background color in hex format (#000000, #a1cef2)
Normal text background
ui.textSelectBackground
Found text background
ui.textSelectBackgroundAttention
Inactive window found text background
ui.textSelectBackgroundDisabled
Text color
ui.textSelectForeground
Other colors
ui.textBackground
ui.textForeground
ui.textHighlightBackground
ui.textHighlightForeground
3. Miscellaneous
Disable addons install delay
security.dialog_enable_delay -> 0