its doesn't happens always and happens randomly. I have observed most of the time when I preview game first time after opening project.
the issue is when I preview project then editor gets locked which means editor becomes unclickable. clicks are disabled. I can't scroll editor, can't switch tabs in editor (layouts, eventsheet). can't click any property or anywhere.
there are 2 ways to make editor clickable again. when I reload preview window or when I open and close developer tools. I have to open developer tools manually by going browsers 3 dots of setting > more tools > developer tools. because shortcut also not works.
I don't know how to post this in bug forum as I don't have steps to reproduce this bug and It nevr happnes always.
Ashley