Paste without formatting (Ctrl+Shift+V). Any difference?

No difference - everything is still double spaced.

Are you one of those typists that ends every line with a hard return like as if they were using a typewriter or do you let your paragraphs wrap at whatever point the software wraps lines.

Note the later folk have fewer issues. The prior group have myriad issues with everything from line wraps when they print to a different printer too poor results from a paste.

Next issue is that the style information would normally come with the paste from the likes of LibreOffice writer, looking into this with some experiments. I found the following

If LibreOffice writer is set to "Default Paragraph style" when the copy is initiated then the HTML that is placed in the clipboard for Thunderbird to get contains this definition.

p style="line-height: 100%; margin-bottom: 0cm"

ie The blocked text is a styled paragraph.

If the style in LibreWriter is set to "body Text" there is no style information passed to the clipboard about how the paragraph should be formatted

In both instances however the text is explicitly delivered as a paragraph, not plain text. Browsers will by default place a blank line before and after See https://www.w3schools.com/tags/tag_p.asp The use of a paragraph will see the style of text shown in the toolbar to be paragraph. So use what you will you will see what the HTML says you see, not what you saw in your word processor that is designed entirely with the concept of putting letters on white paper at it's heart.

Then there is what I see as a Thunderbird bug. Despite the Style being set to body, it is changed to Paragraph by the paste and unless you have already placed some returns in the body of the email before you paste it will set the entire email to paragraph

Personally I do not recommend any form of composing of emails in a word processor because what you see is not what you get.. Compose in Thunderbird will be far more likely to be read and seen by your recipient as you typed it, you pasted text might look good to you on your machine and a absolute layout disaster when Someone get it on their iphone or Android tablet with 3.5 inch display.

Personally I think you may not have actually pasted without formatting (Ctrl+Shift+V) so right click in the body of an email and select paste without formatting and see if your result differs.

Have you tried selecting all the information that you have pasted into Thunderbird (ctrl+A) and explicitly setting the style to body text in the toolbar.

Then there is what I consider to be a Thunderbird bug

So when the information

Hi Matt,

Thank you for that comprehensive explanation.

The cntr-shift-v formula did work and my previous failure was entirely my fault as I used the space bar instead of the "shift" key for my earlier attempt - just call it a "senior moment". The correct procedure is now engraved indelibly in my memory.

Kindest regards, Colin Ballard, 2 october 2025