I have been using WordPress for many years - the problem of code being removed is still present, irrespective of what editor is being used.
Simply put, I edit my code in the text editor (not visual) thus:
[slider id="726" size="blog-width"]
Go back to the visual editor, then back to the text editor - the code is now:
[slider id="726" size="blog-width"]"
Which is hopeless.
Even if I update the page when I first edit in the text editor - the same thing happens.
Does anyone, particularly at WordPress have a solution to this fundamental and site wrecking flaw?