No such option exits beyond "Bookmark" to bookmark the sites. This is what you should be using as Pin tabs can be removed or cleared.

I'm sorry, but bookmarks are not the answer.

When I restart my work computer and open Firefox I need several tabs opened - CMS, issue tracker, mail, etc. It's very convenient to have them pinned since they won't change position while I'm working and I have muscle memory as to where they are. If I close the window/restart computer - everything behaves as expected and pinned tabs are in place. But, if I *dare* to open another window - all hell breaks loose. Now I need to remember to close other windows and only then to close the one with pinned tabs - otherwise I'm severely punished and lose pinned tabs.

So, it seems, if you close the (single) window with pinned tabs - Firefox dev team: "Oh, yeah, pinned tabs are important, let's have them next time Firefox is opened". If you close a window with pinned tabs and forget that there's another one open - Firefox dev team: "Pffff, who the F cares about pinned tabs".

My suggestion: if there are pinned tabs, in any window, once _all_ windows are closed and a new window is opening - add all pinned tabs from all windows to the opening window. It's better to have to sort tabs to their respective windows (rare use-case) than to lose all tabs.

You can look on the Add-ons website for a suitable extension.

I've been terribly frustrated by the same issue for a long time, so I've created an extension to address this. You can find it here.

What it does is that when you close a window, then it'll move all pinned tabs to another active window. So let's say you have window A with 5 pins, and window B with no pins. If you accidentally close window A first, then all pins will be moved to window B. If you now close window B, then Firefox will remember the pins and restore them next time you open Firefox.

Disclaimer: I only just released the first version of the extension, so use with care.