fix(dialog): scrollbar Flash on opening #5121

[bipedal-eel]

This prevents the scrollbar from flashing (Chromium) as mentionend in #5121

[bipedal-eel]

i have found the underlying issue:

the screenshot is console logs in render():

protected override render() { console.log("isOpen", this.isOpen) console.log("open", this.open) console.log("opening", this.isOpening) const scrollable = this.open && !(this.isAtScrollTop && this.isAtScrollBottom); console.log(scrollable) // ... }

Now, scrollable is only set when !isOpening.

const scrollable = !this.isOpening && this.open && !(this.isAtScrollTop && this.isAtScrollBottom);

I tested this a bit and as far as i can tell, this does not break anything.

If it does, an alternative soloution would be the comment you mentioned or setAttribute("opening", "") and doing:

.scrollable .scroller:not([opening]) { overflow-y: scroll; }