TCA:
# Subheader re-enablen für tt_content
t3lib_div::loadTCA('tt_content');
t3lib_extMgm::addFieldsToPalette("tt_content",'header','subheader;;8','after:header');

-----------------------------------------------
-----------------------------------------------
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//-----------------------------------------
// subheader für alle bekannten tt_content elemente re-enablen
lib.subheader = TEXT
lib.subheader {
  field = subheader
  required = 1
  if {
    equals {
      field = header_layout
    }
    value = 100
    negate = 1
  }

  dataWrap = <h5 class="subheader subheaderlayout-{field:layout}">|</h5>
  htmlSpecialChars = 1
  
  editIcons = tt_content:subheader,layout
  editIcons.beforeLastTag = 1
  editIcons.iconTitle.data = LLL:EXT:css_styled_content/pi1/locallang.xml:eIcon.subheader
  
  prefixComment = 2 | Subheader:
}


//-----------------------------------------
// lib.subheader mit jeden type mergen
tt_content.header {
  // Typ Header beinhaltet in .20 eine Subheaderkonfiguration (Überbleibsel oder so)
  20 >
  // füllen mit Konfiguration für aktuelles Projekt
  20 < lib.subheader
}

tt_content.text {
 15 = TEXT
 15 < lib.subheader
}

tt_content.image {
 15 = TEXT
 15 < lib.subheader
}

tt_content.textpic {
 10.15 = TEXT
 10.15 < lib.subheader
}

tt_content.bullets {
 15 = TEXT
 15 < lib.subheader
}

tt_content.table {
 15 = TEXT
 15 < lib.subheader
}

tt_content.uploads {
 15 = TEXT
 15 < lib.subheader
}

tt_content.table {
 15 = TEXT
 15 < lib.subheader
}

tt_content.multimedia {
 15 = TEXT
 15 < lib.subheader
}

tt_content.swfobject {
 15 = TEXT
 15 < lib.subheader
}

tt_content.qtobject {
 15 = TEXT
 15 < lib.subheader
}

tt_content.media {
 15 = TEXT
 15 < lib.subheader
}

tt_content.search {
 15 = TEXT
 15 < lib.subheader
}

tt_content.login {
 15 = TEXT
 15 < lib.subheader
}

tt_content.splash {
 15 = TEXT
 15 < lib.subheader
}

tt_content.menu {
 15 = TEXT
 15 < lib.subheader
}

tt_content.shortcut {
 15 = TEXT
 15 < lib.subheader
}

tt_content.list {
 15 = TEXT
 15 < lib.subheader
}