Every GUI toolkit already "bothers" by virtue of being single threaded. You never see a UI toolkit where this: btn.setText("hello") btn.setColor(BLACK) mi

Every GUI toolkit already "bothers" by virtue of being single threaded. You never see a UI toolkit where this: btn.setText("hello") btn.setColor(BLACK) might show a white-text "hello" for a single frame. If the UI toolkit was thread-safe, though, that would become a possibility.