Welcome all Members of InvisionPower.com

I have a problem with disappear editor on forums while creating topics;C

OK - based off just that then it's very difficult to help. So, fill in some more information:

1. Has it ever worked?
2. When did it last work?
3. if it has worked, and then stopped working, then what changes to the site did you make?
4. Is that the default theme? If not, does it work on the default theme?
5. What is your site URL? Provide login credentials so that people can log in and see what JavaScript errors (if any) are occurring that may cause this.

I suggest submitting an official Support Ticket to IPS so they can take a look for you.