I have a 27" monitor iMac. I set the number of columns to auto because I will resize the program window several times during the day as I move it around. If I set it to auto, 2, 3, or 5 and quit the app and open the app, the columns are set to 4. It defaults and resets to four after every restart. This is a bug and is bad programming. If I pick a column setting on a particular machine, it needs to remember it. If I have to re-setup the screen every time I open the program, then there is a bug
macOS Mojave