I haven't made the jump to v4 yet. And thus, I haven't had the problem. Yet. BUT I suspect I have the answer for the problem IF running Windows. I use a program called UltraMon (
https://www.realtimesoft.com/ultramon/) to manage my multiple monitors. It's got one ability that directly addresses the issue ... It has shortcuts that force an app to run in a window at a set point and set size. I happen to always run Calibre on the second monitor across the lower half of the screen, up to about two inches from the far right side. That way, still can see my email in my web browser and my Notes app running down the far right side. Each of those applications are run through UltraMon's shortcut facility. And I never have a problem with them, no matter what our less than dear friends in Redmond try with their updates.
There aren't many updates to UltraMon. And it's NOT perfect. But it DOES the job and I grow to appreciate it more and more over the years when I (briefly) give the competition a try.