Keyboard Shortcut Switching between Compose Window and Mail

[drum4chops]

I've been searching for a keyboard shortcut that will let me toggle between the Compose Message Window and the Mail Mail Window.
I need this because many times I have to reference an e-mail in the main window while I'm composing a new message.

I'm on a Mac.

Perhaps I'm using the wrong wording to find what I need through searches??

Any help would be very appreciated!

[tanstaafl]

https://support.mozilla.org/en-US/kb/keyboard-shortcuts says that F6 can be used to move to the next mail pane, but when I try that it is just moving between different panes in the compose message window. Control+1 is described as "Mail & Newsgroups Home Tab (Tab 1)". When I use that it moves me to the main window. I didn't spot another shortcut to let me move back to the compose message window.

Under Windows 10 I just hover the mouse over the Thunderbird icon in the task bar and it popups a miniature window for the main window and the compose message window. I then use the mouse to select one of them to change windows. Its more convenient than using the operating systems built-in support for using ALT-TAB to switch windows. I assume OS X has something similar to ALT-TAB.

I am configured to read messages in the "message pane" (part of the main window) rather than in a separate tab or window. In your case you might select the "message window" instead of the "main window".