I have no idea what you mean. Thunderbird does not require donations, so it's puzzling whatever you see. The opening page does encourage support, but that's a voluntary thing. And if you don't like the courteous request, you can turn off the opening page at settings>general. The first option there is the start page. Although Thunderbird is free, totally free to use, it still has costs and depends on its users to periodically donate to ensure that Thunderbird doesn't go the way of many prior email clients.

I've contributed to Mozilla in the past and will again.

My request for help referred to the page requesting a donation that would not go away when I was looking through folders other than my inbox. From a user standpoint it looks alot like my question, "i'm being directed to donate and cannot see my emails." I'm glad no one else has had this problem and you've never heard of it because it's incredibly irritating-much like your response.

Have you actually clicked on a message to replace the panes contents with the email? There is a welcome web page that is displayed that just sits there until an email replaces it. But it is not new, it has been there in one form or another for all the years Thunderbird has existed I think. I certainly recall it from version 2.

yes. I actually tried clicking everything and anything. It didn't work. To start, I pulled up the mail program and tried searching by sender. I made sure I searched by mailbox. When a list of matches showed up in a list I clicked one of the emails and got the page giving me 4 options of how to donate but no viewable email message. I just checked it out again and find that only some of my search results do this - not all. At this point it's not a life or death so i'm going to drop the topic and lower my hand.