Make Magento System Configuration tabs collapsable

gistfile1.js

// Quick'n'dirty
// TODO:
// - store status in a cookie
// - restore status from cookie
// - prevent tab that contains active tabs from being collapsed
// - change icon when collapsed
// - change mouse pointer
$$('#system_config_tabs dt.label').each(function(s) {
  s.observe('click', function(label) { 
    s.siblings().each(function(a) { a.toggle(); })
  })
})