Under Settings, General, Language & Appearance, Colours, do have settings like in the attached picture?

thanks for replying! well, as you see in the attached screenshot, I have «Never» instead of your «Only with High Contrast themes», but no images, I wouldn't know where I could choose and set one... • setting your «Only with High Contrast themes» didn't change anything, the message pane is still gray. • as you can see, I have «White» set as Background color. • what's strange is that if I change there the Background color to another one, nothing happens, the message pane stays gray.

I guess I have to go to the :config settings, but I don't know how and which setting to change thank you and best regards で⊃ Meaulnes Legler Zurich Switzerland

On my W10 system, if 'Use system colors' is unchecked, the Message Pane background is the colour set as Background. Try that, and also see if the background colour is affected by the OS X system theme or colour scheme.

yes, that solved the problem, unchecking «[_] Use system colors» in «Colors < Language & Appearance < General» brought back the color that I set in the «Colors > Background» setting

thank you so much

ド⊃ Meaulnes Legler Zurich Switzerland