If I was a prick I'd say it's clearly your system that's the problem, but I won't do that because I'm not that prick.

SOLUTION: Download the extension, open Add-ons and click its the Install button.

Thunderbird extensions From this link I went to top result > Single-user installation > Thunderbird: Download the extension, open Add-ons and click its the Install button. then clicked more details.

A quick Google search would have helped you out.

Yes. it may well be my system that is at issue. Computers are an extremely complex interaction of software and hardware. But unlike you I am capable of acknowledging that and am completely unoffended by your statement. Sorry.

It may also just have been the daily build I am testing which screwed things up as it appears to have cleared up over time. What I have seen over time are others complaining of a similar issue. it is a cause that I can offer them as a solution I seek, not some generic Google reply that tells me how it is supposed to work.

Please if you have nothing constructive to say. Drop it. Otherwise I will need to use the moderators hammer. I really really dislike using moderation tools, but I will use them if you push me.

In all honesty, I don't understand what you're asking. I'm not being an a**h0le at this moment. Are you asking why the "You have chosen to open: (filename)..." dialogue box appears?

Your post has absolutely no information besides the picture (and the title which is not proper English). I gave information that worked for me, because this is how I understand it; I believe you're asking why that dialogue pops up instead of doing everything automatically (like Firefox does). But ThunderBird is doing the same thing for me. So I showed you how to install the plugin. That is what worked for me, whether it worked for you or not is different.

But, you are obviously offended at me for treating you the same way you treated me... So cut the crap, grow some balls (you look well over the age you should have gotten some) and have some respect for people.

I will grant you my frustration at this abomination of a forum was getting to me. It got the message to the half a dozen regulars that might have shed light. My personal posts are rterely replied to but I still try occasionally. I do not know everything

As you have taken the time to try and understand, what was occurring was clicking the install button in Thunderbird was bringing up the windows dialog. That should not happen. Cause still unknown, but it ceased happening. I suspect something in mimetypes.rdf or the windows registry but really do not know the cause or the solution. What I do know is others periodically come here with the same issue and I can not offer them anything more than "I know" and tell them to download using a browser which is sub optimal.

No I am not offended, I take time wasting poorly. I am warning you about your language use. It is no skin off my teeth regardless of what is actually said about me. I am too old to do more than work on the farm until I retire.

It's no skin off your teeth? Ummm... I think you mean no skin off my nose, teeth don't have skin. Most of your sentences don't make sense, it takes some thinking to figure what you meant. As far as your issue, thanks for explaining it further (that information would have been perfect i the 1st post) that is what I assumed and even the thread i directed you to said it's normal for the windows box to open.

You take wasting time poorly? I find that hard to believe, because you're spending a lot of time to give me a hard time, I didn't use language (care to point the words out?).