Firefox Dev Edition, it randomly closes windows. I typically have up to 3 windows open at a time with anywhere from 3 to 8 tabs open on each, so idk if it's a memory problem and I'm just too demanding? In Chrome, when a window is closed, you can go to "recently closed tabs" and the entirety of that window's tabs are grouped into one entry, so in one click all tabs from that closed window are brought back. It's more like "recently closed tabs & windows". But firefox doesn't have this implemented so I then have to repeatedly open a new tab, open from history, repeat. I'm sure I put too much load on my browsers, but Chrome doesn't do this and I would hope that Firefox would be as much of a work horse as Chrome has been for me in all the years I've been using it. I can retrieve any logs or provide more information to anybody if it helps.

Summary: While browsing with multiple windows of FF:D up, one will randomly close. I actually recall this happening while I had my laptop closed and not in use. The window just closes out and it cannot be restored in any way other than opening each individual tab in history.