Page up/down keys don't work until I click in the email window

The 'Page up' and 'Page down' keys function in the area that has focus. After all, you do not want the 'Pageup/down' operating in an area not selected.

click on a folder near the top of Folder Pane and you have focus in the Folder Pane. Then use 'Page down' key will jump you to a folder near the bottom of the visible area Folder Pane. It does not force a scroll action, so will choose a folder already visible.

Select an email in the Thread Pane, so focus is now in the 'Thread Pane' and use 'Page down' and it will jump to and select the last email that is visible in the display without scrolling.

Whilst selecting an email in the Thread Pane displays the email contents, at this point the focus is still in the 'Thread Pane' because that was the last selected area.

After selecting an email so it shows in the 'Message Pane', you need to then click on the contents of message to get focus on the actual message; the Pageup/Pagedown keys will operate on the contents of the email. Depending upon size of email, the page up/down will jump the equivalent of size of scrollbar/the visible area.

The up down arrow keys function in whatever area is in focus/selected. So if you clicked on eg: Inbox folder in Folder Pane and then used up/down arrow keys, you would navigate up/down the Folder Pane one folder at a time.

If you select an email in the 'Thread Pane' - list of emails - the up/down arrow keys would move you up/down the list, one email at a time.

If you selected an email to show in 'Message Pane' and then click anywhere in that opened message, that message now has the focus, so the up/down arrow keys will now have the effect of scrolling the message, but the number of lines it scrolls depends upon your preference settings in 'about:config'. In my case it moves three lines because I have this setting: toolkit.scrollbox.verticalScrollDistance Value is 3

Hope this info helps.

Thanks for your response! I definitely understand how the Page Up/Page Down keys work in the different panes and, for the most part, they work as expected.

It's is when I select an email to show and it opens in a new message window that the Page Up/Page Down keys do not work unless I use the mouse and manually move the focus into the actual message window.

So I guess what I should have said is that the focus does not change to the message window when it opens to display the email. Since the focus doesn't change, the navigation keys don't work on the email unless I manually change the focus.