Has anyone seen this issue? About once a day, I can't get the Hangout chat pop-up to appear. I can see under any given contact that I've been sent a message, see the first few words, the contact is highlighted, but when I click on that contact, the pop-up doesn't appear to see the full message or the ability to respond. I only get their contact information box. The same occurs when I want to initiate a chat. The only resolution thus far has been to restart my machine. I'm running Hangouts under Chrome Gmail, Windows 8.1. 
Can't start a Hangout conversation
gmail;google chrome;google hangouts