After upgrade to 10 - when I use dark theme - also backgorund in new mail window is dark…
There is no any option to change it (only options for use dark theme and light background is for preview window)
in v9 in dark theme backgorund for new mail windows was white.
For now is unusable - can’t see how mail will look in real.
Sorry, in version 9 place where type text was white - if options was configured like here. You could choise it. In v10 is bug - options is available but not working. I talk about options: background colour from theme or like You want.
Those are my V10 screenshots “that do work” as in the 2nd screenshot above, with the white background and the black text in the compose window using the latest V10.0.3351.
If that’s not working for you, then i don’t know why.
We changed this back to the way it was in version 9. Please download the latest version in the Release History, so the version @cyberzork mentioned above.