Comment 17 for bug 29802

I have a patch which seems to help with the issue.
With the patch, an error appears the first time the User Administration panel is clicked, either:

Could not retrieve catalogs from server
MySQL Error Nr. 0

or

Could not retrieve schema table definitions from server
MySQL Error Nr. 0

But there appear to be no other ill effects, and the user administration panel is accessible. The error occurs because the patch causes an error to be returned for a mysql query, if an existing query is already in progress. In addition, the error occurs at a point where the program would otherwise have locked up completely. The parallel queries are not expected to occur within the program - appears to be due to some differences in signal generation in recent libgtk2.

There doesn't appear to be much else that can be done without an overhaul of how the locking is done in mysql-admin.