If I was a native widget toolkit designer or web developer I'd implement a rule that all layout changes must be rendered and on the screen 150ms before input ha

If I was a native widget toolkit designer or web developer I'd implement a rule that all layout changes must be rendered and on the screen 150ms before input handling can use them. Lag compensation for local user input. If you click a button at the same time it moves, you should still click what was on the screen at the time you pressed the button. Yes, I know this effectively means having to keep two copies of the widget tree (one for input and one for output) and applying all changes as diffs. Don't care. I'll buy more RAM.