Hi,
Query statistics tab greatly increases page load time in my browser - I get about 5s delay before tabs are created which is IMO too slow. Removing "<?php printQueryStatistics(); ?>" from the code decreases it to less than a second and causes page load event to be fired about 10 seconds earlier (at 2nd second instead of 12th).
I think this should be fixed, eg. by initializing chart only when user actually navigates to it.