I play on a windows 7, 64 bit machine using chrome as my browser.
When the new daily quest is offered (12 am est), the screen darkens and the new quest pointer point at the quest menu. Selecting the quest menu and the new quest reveals the new quest, but the screen darkening never goes away and it prohibits user interaction with the game. Relogging seems to be the only way to remove this effect and return control to the user.
