My html editor is disappear today. I didn't do anything.. I couldn't show it while I was using google chrome browser but I can use it in Internet explorer and firefox but today, I don't know why, there is no toolbar (while adding a label) in none of the browsers.. what can be the reason for it?
You're probably using a version lower than 1.9.11.
I have experienced the same issue with 2.1.1+
Perhaps an upgrade may help.