I running W7 with 4GB, using two regular Windows and one Private Window. When the system memory gets used up running Gmail, G-Maps, G-Docs in Tabs (this is confirmed by the Task-Manager running in a Tab); Firefox starts to lock-up, closing the Tabs frees up the system memory, but latest version Firefox does not recover and has to be restarted.
Here are the detailed workarounds for saving the Private Window Tabs with Bookmarks. Tabs not to be saved are closed by clicking on the Tab "x" (the Window is not updated) and reducing the Window and restoring it (updates the Window). Bookmarking the remaining Tabs is done the same way. Then the Private Window is closed, none of the Tab-Tools work when Firefox is locking-up. Are there any Tools to manually record (dump) the internal state of Firefox? If these tools are added, "File Menu," (The very Top left of Firefox Window), is not seem to be affected by this bug.