[JKT]

Conversely, open and close a pane (no matter where or what size your window is) and the window content resizes every single time which is far more annoying - this is no advantage to the split pane at all as it happens anywhere and everywhere, fullscreen window or not. With a drawer this only ever happens in the one extreme case that you describe (when your window is near full/full screen and it has to resize the window to fit the drawer).