After saving LaTeX preamble settings, extra backslash is added to them

In "Site Administration" we can see "Modules" then "Filters" menu where we find "Settings" for "TeX Notations". When we click the "Settings" we see "LaTeX renderer Settings", especially there is "LaTeX preamble" settings.
After I changed the setting a bit and save change then an extra backslash is added to them like
"
usepackage[latin1]

" and even if I pressed
"Reset to defaults" button, it is not corrected, further if I press "Save changes" once again then there are 4 backslashes and so on. So we can't get correct LaTeX preamble anymore.
I'll attach a screen shot which might help you to understand the problem. Thanks.