Q2A 1.8.6: the wysiwyg-editor works with linux clients, tested with firefox and chrome.
With Windows clients the place of the widget is just empty. Also tested with firefox and chrome and with different Windows clients.
interestingly enough the wysiwyg-editor works with this installation. I'm using this editor right now with a Windows client.
edit: on Mac-OS it works with Safari and it doesn't work with chrome.
Switching on the console in firefox shows the following error:
Uncaught TypeError: c[a] is undefined
Googling for this error shows, that it is a problem with ckeditor.js. Unfortunately the solutions didn't work for me.