Hello there Wayne knight We have read the messsge We try to help

You will have to accept the problem with the limited implementation of the image mode as the Supernova version has created this layout.

There is also no answer to this for so long, this will be resolved in further versions of Thunderbird over time as the notifications pile up thanks to you as a user.

Greetings Firefox volunteer.

I cannot accept your answer as I have the same version of Thunderbird installed on my desktop and it does not have the same problem.

Apparently the impossible is not really impossible after all.

A search for the term "pane" among the several thousand advanced preference settings yielded a list of about 20. Among them is one called mail.pane_config.dynamic which was set to 2. Clicking on the edit button and changing the value to 0 changed the mail panel layout from vertical to horizontal.

Wayne, are you still seeing that the layout optoins are locked?