Having done a few such forms in the past, it was easy enough for a simple dialog with a list, two buttons and a text field, but it quickly got unwieldy.
Which was okay back in the day. Everyone had low display resolutions, so simply scaling a window's controls when resizing was okay. No need for responsive layout and even too fancy layouts, I guess. But what we got later with anchor in WinForms, layout panels in WinForms or WPF, layout managers in Swing, and CSS layout die help reduce the math you'd have to do yourself, especially for more complex layouts or even when the layouts change due to different requirements.
