Kile has ambiguous shortcuts which result in the following string used
as KConfig key for the dontShowAgain KMessageBox checkbox:

Find in Files...Normal Fraction - \frac{}{}Alt+Shift+F

However KConfig doesn't like it:

"Invalid escape sequence \"\\f\"."

and the 'f' character after the slash is removed from the key, breaking the
dontShowAgain functionality.

This patch removes all backslashes from the key, before passing it to
the messagebox.

Open Kile, check the dontShowAgain checkbox, close Kile. Open again Kile and
make sure the messagebox is not shown again.