Visual en text editor tab problem

Hi, after updating to wp 4.5.2. suddenly all the buttons on the visual edirot tab disappeared. And, by default the text tab is active. But clicking the visual editor tab is doing nothing!! I disabled all plugins, de-cached, changed my theme ….. still the problem is still there. For all useraccounts. Does anybody have an explanation or better a solution for me?!?
thnx.
regards John