as shown in the community's vision, a constructive feedback is allowed. In my main, a criticism is a constructive feedback. I come to the point.
It concerns the handling of my first and only bug report in Bugzilla  in twofold aspects. Furthermore concerns it my personal position to Firefox. Unfortunately, I get more and more errors which force me to use an alternative browser. After below described experience, I'm in doubt to report bugs in the future.
I hope that anybody can blow my grief away.
1. simply closed
To help to find the error, I was asked to install and downgrade step by step a Firefox, till the error disappears. I had not the resources to give the requested support. Finally, the bug was simply closed.
Is this the right way? I think not.
What is the situation now?
The bug still exist and will appear at other users too. This bug makes it impossible to use Firefox. No any menu can be opened, not in head menu nor the context menus. Users, confronted with this bug will use an other browser thereafter.
End users, or users not able or willy to install any test stuff and be involved, cannot report bugs sinful.
From my point of view, such a bug should not be simply closed even if the reporter cannot give the support. By the way, the bug report itself is support.
2. questionable method
The second aspect of my criticism is the kind to find the place of error. I described the error so, that a developer can recognize the bug as initialization bug and where it happens. Than I was asked to install and downgrade step by step a Firefox, till the error disappears. I think this method is absolute not helpful, because: - possible the error exist from begin on - possible that the initializing situation of the RAM is so, that the error do not pop up in the test environment. - if we find a first non error version, we have an other RAM-constellation too and the initialization could be given by accident
And if we would have found a version, we still not know where in the code is the leak. And what we than had to do, we could do it immediately at the current version. Involved developers should know where in the source initializing happens or needed is and find the place strait forward. If it isn't so, the source code goes out of control.