Widget affecting screen positioning

but isn't this actually a race condition?

It's actually fine in JavaScript. JS is itself normally only single-threaded, so if you're inside a function, no other JS is going to be able to run and mess things up for you.

It's just when you first start your function. For example if you do:

setInterval(function() {
 // here
}, 1000);

Then you have no idea what would have run before your function started.