Apparently, our resizeObservers were calling each other and making an error in recent Chrome browsers. So we adjusted as follows - only observe if the part was pressed on.
zid("part1").addEventListener("mousedown", ()=>{
part1Observer.observe(part1);
});
zid("part2").addEventListener("mousedown", ()=>{
part2Observer.observe(part2);
});
document.addEventListener("mouseup", ()=>{
part1Observer.unobserve(part1);
part2Observer.unobserve(part2);
});
function outputsize() {
lastHeight = (zum(zss("part1").height) - 0) + "px";
if (horizontal) {
zss("part2").height = lastHeight;
}
}
var part1Observer = new ResizeObserver(outputsize);
function outputsize2() {
lastHeight = (zum(zss("part2").height) - 0) + "px";
if (horizontal) {
zss("part1").height = lastHeight;
}
}
var part2Observer = new ResizeObserver(outputsize2);