Problem With Mail App Mac OS Mojave

Mac
#1

I have a 21" iMac 2017, and the Mail app has started acting funny. In the normal view the column that lists the actual emails keeps automatically resizing down to minimum size. This means that in order to see what the emails are about I have to drag the size of the column to the right. I normally have it set half way across (I’m running Mail in full screen), but in about 4 hours it automatically resizes itself to the minimum width. This is starting to get really annoying and has only recently started happening.

Is anyone els having similar problems and does anyone know of a fix?

Thanks.

#2

When does the resizing happen, when do you notice it? After you switch back to Mail from a different program?

#3

There is nothing specific, mainly after using Safari, but it seems to be time related - it does it after several hours not at a specific time.