1440756 - Preferences-Privacy-History option "Always use private browsing mode" disables "Clear history when Firefox closes" option

Status: RESOLVED DUPLICATE of bug 463607

(Firefox :: Private Browsing, defect)

Description

[brianfaull+gh]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/604.5.6 (KHTML, like Gecko) Version/11.0.3 Safari/604.5.6

Steps to reproduce:

Navigate to Preferences, then "Privacy & Security" tab, History section. Selecting "Use custom settings for history", then selecting "Always use private browsing mode" disables the checkbox for "Clear history when Firefox closes." I believe the "Clear history..." checkbox should be enabled no matter if "private browsing" is enabled or not. This fact can cause certain data to be erroneously stored after Firefox restarts.

This is Firefox 58.0.2



Actual results:

When "Always use private browsing mode" is enabled, the checkbox for "Clear history when Firefox closes" is disabled. The problem is that I would like to delete all history, cache, offline data, etc. when Firefox closes. Selecting "Always use private browsing mode" disables the "Clear history..." checkbox, AND certain history history (such as "Cache" and "Offline Website Data") seem to be saved (by inspection of "Cached Web Content" size) upon restart, depending on previous choices inside the "Clear history when Firefox closes"  "Settings..." dialog. The value of the "Clear history..." checkbox (selected or not selected) is displayed / saved even when the option to change it is greyed-out; both options can be set by toggling "Always use private browsing mode". 


Expected results:

Either...
* All data (not just some data) should be deleted upon restart if I select "Always use private browsing mode", or "Never remember history"
* Allow the configuration of the "Clear history when Firefox closes" no matter if "Always use private browsing mode" is selected or not. 
I prefer the latter, because it seems less confusing from a UX perspective.