Try and edit a formula (example, don't use quick edit).
Try and add an operator (for example, a backslash) by clicking on it from the Operators set.
Notice it gets added as "backslash", that is, by its name, rather than as "\".
This happens for several other operators and marks.
"\backslash" is the correct sequence for a backslash in LaTeX, as "\" itself is a special character. Are there any problems with the rendered formula?
I had misunderstood the problem.
Per our friendly commenter at de.wiki,
"The problem has nothing to do with the "Operators" window, rather with the LaTeX-Syntax-relevant character "\" itself. I had to use this character in a formula (just through writing it as "\" in the editor mask) and it was replaced during saving with its ampersand equivalent, something like \. But as I am not longer able to reproduce the error -- for whatever reason -- , I propose to close this discussion as not reproducable. "