I doubleclick on an email in Inbox (IMAP) to display it. A new window opens, and I briefly see the message displayed. Then the window clears and the hourglass (circle of dots) is displayed, sometimes for quite a while, before the message is redisplayed. PLEASE, display the message while doing whatever the hourglass represents, so I can begin reading, even if some part of the message is not yet available.
It will be fixed in the upcoming version 5.