When opening LR Classic 9.2 it maximized its window size to take my entire screen no matter what the window size was when I had closed LR. I have an iMac with Catalina 10.15.3. Uninstalled LR 9.2 and installed LR 9.1 to fix the problem. Its was too much of a PIA to have to resize the apps window every single time I opened LR to justify the upgrade's features.
Question: why would you WANT the window smaller than the size of the screen? I don't understand wanting that. I use 2 monitors, my iMac with the Grid View (as big as possible, but not Full Screen), and the 2nd monitor with "Full Screen, Loupe-Normal". PS-moving a window around to get at what's behind it is completely inefficient, use Command-H to hide it. -former Mac IT Pro.