Symptoms

"Customize Colours and Dates" section can't be expand via Administrations > Look and Feel > Edit Configuration.  

Besides that, all navigator menus will not be click-able except 'Administration' in the same page. It will be looks like:

Cause

This is due to a bug caused by a plugin called "Admin Helper". Please refer to this  JRA-29451 - Getting issue details... STATUS for more information.

Resolution

1. Remove the plugin until the bug is fix.
   or
2. Temporarily disable the "Admin Helper" plugin via  Administrations > Plugins > Manage My Plugins, then you will be able to do the configuration in Look and Feel, you can enable it after that if you still need the plugin in other purpose.