Is this a private project? If so, you may be seeing the outcome of fixing 0005425. For private projects, those at or above the "private_project_threshold" as well as those explicitly added to the project may be listed.

Yes it is a privat project, but it doesn't have a parent project. I have a user who is developer and developer in private project A but he can be assigned to private project B. Of course this user can never see private project B in his project list, seems very confusing.

What is the status of this bug? In my opinion this is very important, because I can assign bugs to handlers who aren't members of this project, so what sense does it have? The assign drop-down list is unnecessary long and I can see all handlers of all projects in database, for our purpose this isn't desired in projects with handlers of sub-companies who are only assigned to one project.

I think it would make sense if a handler is members of a project that he can be seen in that project and all subprojects, but not any project else.

If this won't be solved, can anybody help me to fix this for my own?

To summarize, you are seeing developers listed in the Assign To: list on private projects, where they are not listed. What have you set for $g_private_project_threshold? The default setting of DEVELOPER could be causing this.

$g_private_project_threshold = ADMINISTRATOR in my installation. We only have private projects.

Every handler can see every other handler in the assign to drop-down list here. Isn't this the case too for bugs.mantisbt.org? I can't see, because i am only reporter.

Do you have a disjoint (array) selection for the $g_update_bug_assign_threshold, or $g_update_bug_threshold (as shown in the Manage -> Manage Configuration -> Workflow Thresholds page? If so, you may be seeing the same root cause as 0005697. Updating the core/project_pai.php file from CVS would fix this.

I don't know exactly if I have a disjoint selection because I didn't understand (sorry for my poor english) but the CVS Head of core\project_api.php absolutely solves my problem. Thx for help.