double click opens the message either in a new tab or a new windows depending on your chosen preference.

This add-on is the one I use for that honking great message header pane. https://addons.mozilla.org/en-US/thunderbird/addon/compactheader/

I would use the addon to reduce the size if I can not remove the message pane, The grey message pane is redundant as the the list of downloaded emails have the same information thus the grey preview pane is just a waste of space blocking the email making me scroll or double click for larger view. It would be nice to hit a key and just get a full page view of the email with out a preview of subject etc in the way.

You know I think you should just install the add-on and accept that there will be a one line header with the message subject and sender shown in it. Having one line is hardly onerous. As there is no way to get rid of the header entirely your choices are fairly straight forward.

Otherwise turn off the reading pane. (pressing F8 turns it on and off) then either double click your mail to open a tab or single click and press enter. But you will still have a header pane, but you will not be able to see the message list and header at the same time.

Downloading the addon now thanx for your help Bru..

I downloaded the addon it would be nice if they told you how to install it????

You could just drag and drop your xpi file onto Thunderbird's add-ons window.

How to install add-ons: http://xenos-email-notes.simplesite.com/416814616

ok I dragged it into addons, after updating the thunderbird version it installed and was able to make the preview pan smaller, everyone thanx for your help, it's appreciated

Just for completeness for the next reader of this thread, you could use the knowledgebase article. https://support.mozilla.org/en-US/kb/installing-addon-thunderbird

Thanks many times over this add-on worked wonders for me.