Impact is not a crash as "crash" of course, the system keeps working but it's getting close to impossible.

I'm unable to reproduce this on any of my installations, and I use Firefox 3.0 and 3.5, Opera, and IE8. Unless you can determine the root cause of this issue, and/or submit a fix, I don't think there is anything we can do at the moment to solve this problem.

I've encountered the same problem as well. 1.2.0rc2. Firefox 3.5.
No problems on IE. The workaround is of course to use IETab add-on for Firefox.

Furthermore, Firefox 3.5 caches everything and unless I click on refresh, no update is seen on the form or on view.
Again no problems on IE.

With add-on "Corel IETab" it works! I can change my project and add new issues.

Maybe this work-around will help in te search for what's realy happening.

Thanks!

Oops... Now I get a "Application error#2800" if I want to add en second issue.

You must be having caching issues, which is what causes the 2800 error during normal usage. Do you have a reverse proxy in front of your webserver, or does your network access run through proxy servers?

Mine runs through proxy servers.

I've got erratic "Application Error #2800" message too. #2800 happens on both IE and Firefox. I have to clear cache and cookies to resume. It's pretty annoying. Is there any setting to resolve this issue.

You'll need to have your proxy server configured to not cache pages from Mantis, or configure its cache to expire immediately for Mantis pages. Unfortunately, there is no way, that I know of, to "fix" Mantis to work in this situation, because it is your proxy server that is serving cached versions of pages from Mantis.

Re Application Error #2800.

When I look at the HTML page source when this error #2800 occurs, I do see a token as hidden input. But when it gets to the function form_security_validate(), it can't find the token in the buffer, hence error #2800.

This is where it fails in form_security_validate:

Check if the token exists

if ( isset( $t_tokens[$p_form_name][$t_date][$t_input] ) ) {
return true;
}

Any idea why proxy server would mix up the token and token buffer?

Thanks.

The problem is that your proxy server is caching pages inappropriately, and serving the same cached page (including security token) on multiple requests from the user, rather than requesting a new page from the server. There is nothing Mantis can do to overcome this issue (that I know of), short of the (existing) option to disable form security validation.

Geert-Jan, this issue is not reproducible with current version of MantisBT.
Feel free to reopen the issue if there are still problems after upgrading.