So I have an extension which I can choose as a content element. It has his own tab ("video") but also uses the standard tab "general" and some special tabs where I can configure the extension. Is it possible to add a "RTE" text tab (like in "Text with images") to the "general" tab? It just uses a "header" field.. but I really need the option for the editor that he can add RTE text in a additional field (like in "text with images".
In the ext_tables.php of your plugin add the bodytext column back to tt_content:
...
t3lib_div::loadTCA('tt_content');
// this line is probably present already:
$TCA['tt_content']['types']['list']['subtypes_excludelist'][$_EXTKEY . '_pi1'] = 'layout,select_key';
// add this line:
$TCA['tt_content']['types']['list']['subtypes_addlist'][$_EXTKEY . '_pi1'] = 'pi_flexform,
bodytext;LLL:EXT:cms/locallang_ttc.xml:bodytext_formlabel;;richtext:rte_transform[flag=rte_enabled|mode=ts_css],rte_enabled,';
...
This will not be in the 'General' but in the 'Plugin' tab though. I'm not aware of a way to add it to the 'General' tab.