Restore Previous Session in Firefox not working right

[howiem]

Win 7 Pro SP1
Sandboxie 5.06
Firefox 42.0
Eudora mail 7.1.0.9

This may not be a Sandboxie Issue but I am not sure
I tend to keep a lot of tabs open in Firefox, and the Restore Previous Session function seems to be working fine except when the browser is closed and I click a link in Eudora email. Then, only one tab opens in the Default sandbox, the one I clicked in the email.
Before Firefox 42.0 and Sandboxie 5.06 the previous session was restored along with the new tab.
In History when I click "Restore Previous Session", it only restores the tab I opened from the email.
I can, of course restore the tabs one at a time, or use saved bookmarks, but that is not very productive.

As I noted above, I cannot tell if this is a problem with Firefox or Sandboxie, but I thought I would try this forum before taking it to Mozilla.