In macOS you can set up a global keyboard shortcut for the '''Move Window to Right Side of Screen''' command via '''System Settings > Keyboard > Keyboard Shortcuts...'''. In most apps that support the Move Window to... commands, this will simply move the window to the desired side of the screen when the key combo is pressed. However, in Firefox the key combo will start the animation as normal but the window will then bounce back to its original location. It's only when the command is activated via a keyboard shortcut that it does the bounce back behavior, though; the command works as intended when activated from the Window menu in the menu bar or from Option + green button in the top left of the window. The key combo I set up was Shift + Option + Command + Right Arrow, but I've also tried a couple of different key combos and they all did the same bounce back behavior. I've tried it on machines with different versions of macOS (Sonoma beta and Ventura) with the same result. The bounce back behavior also effects the '''Move Window to Left Side of Screen''' command.