Lightroom Classic window not able to be resized

I'm not sure if this is user error, but for the first time tonight, after using this app for about 5 years, the LR Classic window is stuck at the full size of my screen - not exapanded with the green, double-arrow button, but just stretched out accross the whole screen - and though I can move the window around, I cannot shrink it vertically or horizontally. I both force quit and updated the app and it still reopens with the same issue.