Not sure if this is a bug, although I can’t really see it as intended behaviour.
If you set pane widths (so sidebar, messages list pane, and reading pane), and then move eM client to another screen that is smaller, it changes the relative width of those panes completely.
So now, for example, “columns view” (not really sure what it’s called) in the messages list pane is no longer columns view, but is condensed view.
Moving it back to the first screen does not put it back how I had it.
Expected behaviour would be to keep pane widths percentages of the screen consistent, and to keep “column view” on unless I change it to condensed view.