User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:82.0) Gecko/20100101 Firefox/82.0

Steps to reproduce:

Suddenly, in this new release (78.4.0 (32-bit)), it is no longer possible to narrow a window sufficiently:

1. Pick an existing message.
2. Right-click the Subject.
3. Select menu item Open message in New Window.

Actual results:

The resulting message window cannot be narrowed as before to make the message easier to read for older eyes.

Expected results:

It used to be possible to narrow the window to (say) 5 words wide, for easy reading.

Note: the narrowing appears to be due to a misguided desire to keep the following buttons all visible:
Reply|Forward|Archive|Junk|Delete|More

I would rather be able to read the message easily than to see all of these buttons at once, no question about it.

I will attach a screen shot showing the minimum width now allowed, which is not narrow enough.

Comment on attachment 9186375 [details]
WRONG IMAGE

PLEASE REMOVE THIS IMAGE

WRONG IMAGE

Please delete the wrong image. It contains someone's private information!!!

David,

Here are two things you could do.

1. Install the Message Header Toolbar Customize extension and modify the buttons in the header.
2. Use the zoom function in the Menu bar using View > Zoom.

Item #2 saves you from installing an extension.

Thank you, but neither meets my needs. The first would make the buttons unusable when I'm not in narrow mode (message displayed in a separate window). The second makes the text too large to read easily. I need short lines of small text so my eyes don't have to scan left to right such a long distance to read fast.

So I would prefer that this new bug be fixed, and soon if possible.

Perhaps, if the problem is a button customization feature, providing an option so that the user can get the previous behavior, where a very narrow message window was actually achievable.

This is with the extension installed and configured for icons only.

That won't work for you?

Yes, I think that would meet my needs; it looks good. I've installed the addon, but there are no instructions. How do I minimize the tool buttons?

Ah, I see: it immediately minimized the icons. I can now narrow the message windows. Thank you.

This bug report can be closed.

Thunderbird is again showing this problem in limiting the minimum width of the Message on the Index > Right mouse click > Open Message in New Window action. It did this because it forgot my setting of Open Message in New Window > icon row (right-click > Customize toolbar).

So the bug for the workaround is that Thunderbird sometimes switches from icons-only to text configuration, forgetting my selection of "icons".