Friend list disappeared for the second time.

I'm having this bug where my friend list completely blacks out (changes color to blue if I queue a game). First it happened on last Tuesday, where everything was fine until I've updated window and came back to the game. I queued up a round to check if it's my internet connection with the server causing the problem. But I was able to play the game without problem, and I could chat with people in-game. One thing I've noticed though, was that I couldn't connect to chat during entire pick & ban screen. When I turned the game on the next day, friend list came back up, so I thought problem was solved. Now I'm here because... Yes, you guessed it. it's happening again. So far I've tried full repairing client, rebooting computer and reconnecting to internet and nothing worked. I hope you would solve this issue as soon as possible. Thanks!