Font reduction after moving messages

Hi! For some time now I have a problem, which I did not have before: when I move the Inbox messages, which I correctly display in font 9 as set, to other folders, the text is reduced to a much smaller size (in several cases it becomes unreadable…), while before it remained the same.
I can’t find a way to solve it in the settings, can you help me, please?

Thanks, greetings to all

Maybe you are changing the zoom level.

To reset it, click somewhere in the message body then use Ctrl + 0

WOW! I didn’t even know this option existed.
Perfect, solved.
Thank you so much