Are you able to reproduce on https://www.mantisbt.org/bugs ?

To be honest, no I can't reproduce it here.

Check your browser console for errors or warnings.

rocket-loader is not part of Mantis.
Maybe it's added by you , your providet or a 3rd party plugin.
Not sure if it's causing the issue, but you are obviously not running a standard Mantis.

legend8139,

This is not a bug or feature request for MantisBT (you are asking for help on how to deal with issues introduced by your special configuration). I am therefore resolving this issue as "no change required".

Please use the forums to get support on customizing and using MantisBT (refer to http://www.mantisbt.org/support.php for links and further details).

Feel free to reopen the issue if you finally should find that the issue can be reproduced using a standard Mantis installation.