495579 - Unchecking "Automatically start in a private browsing session" takes out of Private Browsing

Status: RESOLVED INVALID

(Firefox :: Private Browsing, defect)

Description

[Ivan Naitana]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1pre) Gecko/20090529 Shiretoko/3.5pre (.NET CLR 3.5.30729)
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1pre) Gecko/20090529 Shiretoko/3.5pre (.NET CLR 3.5.30729)

When using the browser in "Automatically start in a private browsing session" mode, you're not allowed to get out of Private Browsing mode.
But if you unselect that checkbox in the options, you're automatically taken out of Private Browsing, without any notice, and while still displaying the same tabs.

Reproducible: Always

Steps to Reproduce:
1. Tools->Options->Privacy->Custom Settings->Check "Automatically start ... in a private browsing session"

2. Close Firefox

3. Open Firefox again. It now is in Automatic Private Browsing mode. You're not allowed to stop Private Browsing and the "(Private Browsing)" is not in the title bar, since you're supposed to stay in that mode for the whole session.

4. Load some pages.

5. Go again in the options and uncheck "Automatically start ... in a private browsing session". Confirm.
Actual Results:  
It appears you get taken out of Private Browsing mode, and it happened without any prompting or noticing. You can't notice it by the title bar, because you were in automatic mode and it already didn't show "(Private Browsing). Worse of all, the pages you opened while in Private Browsing are still there, but every move you will make in them will be remembered.

Expected Results:  
As I see it, unchecking that option should apply to next restarts, but not to this session. Since in this session I weren't allowed to get out of Private Browsing in the regular way, and since my pages are still there, I would assume I am still in Private Browsing.

Comment 1

[(no longer active)]

This behavior is by design.  Like the rest of the Firefox preferences, the "Automatically start in private browsing session" preference takes effect immediately.