have you installed any plugins recently, if so deactivate them and try again?
switch to the default theme and try again, check if the issue persists (always do the testing on default theme, please)?
check your firebug console in Firefox for any JS errors, if there's any, please provide a screenshot of the error. See this tutorial: https://docs.oxwall.org/faq:parse-error-troubleshooting
thanks for the help problem solved.