Hi Joe, is this problem on a specific website (like Gmail, Yahoo mail, Outlook) you are viewing in Firefox, or is this problem in the separate Thunderbird email program?

If it's a website, maybe someone knows how to re-display the preview/reading pane, or maybe you can see a button for it right above the Inbox somewhere, or a Layout/Settings option.

If it's Thunderbird, a moderator can move your question over to that forum.

Apologies and I should have mentioned that I'm using Thunderbird to combine two different Gmail accounts. Everything was working well until I upgraded to the latest version of Firefox. Are you able to re-direect this to someone who could help me? Many thanks. Joe

What I should also have mentioned is that the action boxes like delete, save, forward etc are also missing. Thanks Joe