When you paste text from another source into the the reply tab of a message the message does not look the same as in the popout compositor nor the final sent message. I have only experienced this with empty new lines, but there might be more differences.
Create a plain text with a bunch of empty new lines in a text editor. For example:
This is a random text with a bunch of new lines here two lines above
Copy that text into the reply tab of a message. Open the “popout compositor” of the same message. You will see that the the preview of the message is different between both places.
The message should look the same in the reply tab and in the “popout compositor”.
Here is the example above in the reply tab:
The same message opened in the “popout compositor”:
- OS and Version: Windows 10
- Installation Method: Installer
- Mailspring Version: 1.10.3