What could cause the Wysiwyg module / CKEditor randomly disappearing and coming back? I've successfully installed and configured the Wysiwyg module with CKeditor. However, it keeps disappearing. First it disappeared when I enabled another module (cannot remember which, but thankfully it wasn't necessary so I could disable it again). I was just lucky to figure that out.

But now it disappeared again, and I don't know what happened this time. I didn't install any new modules.

Any ideas why this is happening? Is the wysiwyg module too unstable to use? If so, what's the alternative?

EDIT:

The issue keeps coming back, but I have discovered something new: if I disable a module (and optionally enable it again), apparently pretty much any module, then the wysiwyg editor appears again(!)

So it seems any change in the modules installed brings the editor back. I have only tested this in localhost, if that has anything to do with it.
go to modules and find jQuery Update module, and put it to version 1.8
That should fix the issue.