The default behavior: When a message is selected in the mailbox window, the Reply button will start a reply message to that message. Reply sends only to the sender of the original email.

I'm trying to guess where your Account Settings or Settings (General) are confusing the Thunderbird Reply function.

Do you have the Reply button in your Unified Toolbar when you have your message list open? Do you click that button when a message in the list is selected (colored) in order to reply to that message?

I have the same problem. I tried putting the Reply button in my Unified Toolbar and clicking it to reply to the selected message. The cursor still defaulted to the search box. I have to say this is a deal breaker for me. I can't spend the rest of my life repositioning the cursor for every reply I make! Thanks for your help.

I wish I could suggest something, but I can't duplicate the problem, and thus I can't fix the problem and tell you how to do it. Curious, though: What does the pop-up balloon say when you select a message and then hover the pointer over Reply? See mine below. Click for a larger picture.

@colin_irvine Another curiosity: What version of TB are you running, and on what operating system?

Thanks, Wisewiz, for going to the trouble of trying to sort this.

When hovering over the reply button the pop-up balloon simply says "Reply to the message". I'm running 115.4.1 (64-bit), OS is Windows 11 Home Version 22H2.

Colin