Joomla! values community feedback for catching and reporting issues in the CMS. The bug tracker provides a central location for reporting these issues.
The Joomla! Issue Tracker is the current location where issues are tracked and you can report new issues here. This tracker is used for all Joomla! releases. More detailed instructions regarding this process can be found in the Joomla! documentation here.
When you believe you’ve found a problem in the CMS the first thing you can do is to check the bug tracker to see if that particular issue has been listed already. This can easily be done on the tracker by filtering the list of known and pending issues. Once you’ve verified there are no other current listings for an issue you can then post it.