I had a similar problem (text in editor goes white and formatting bar disappears) and it turned out to be my ad manager plugin (Simple Ads Manager) and the fact that I had Adblock Plus enabled.
Might be worthwhile disabling Adblock on any wordpress sites that you manage. If that isn’t the problem I can’t really offer any other advice.
Took me a while to work this one out too.
I was having problems with the visual editor in Chrome. The text went white and the formatting bar disappeared. I disabled AdBlock Plus and the problem went away. This is worth noting.
