+++ This bug was initially created as a clone of Bug #856018 +++ Create a Firefox UI test that covers this MozTrap test: https://moztrap.mozilla.org/manage/case/6557/. STR: 1. Launch the browser. 2. Open the Options (Prefereces) dialog on the Privacy tab. 3. Select "Use custom settings for history" for "Firefox will:" and check the "Always use private browsing mode" checkbox. 4. Cancel the operation from the Restart Firefox dialog that just appeared. 5. Make sure Firefox keeps using its regular session/mode now. 6. Repeat steps 2 and 3. 7. Click OK on the Restart Firefox dialog that just appeared. 8. After the restart, make sure private browsing mode is being used (even after performing other manual and automatic restarts). 9. Change the Options|Preferences->Privacy settings to "Remeber history". Make sure Firefox works fine back in its regular mode. 10. Repeat steps 1 to 9, but use "Never remeber history" instead of "Use custom settings for history"->"Always use private browsing mode". Expected Behavior: Changing from regular mode to permanent private browsing mode, including cancelling it, works fine. Firefox changes modes according to what the user selected.
We are currently blocked by some missing libraries here.