We weren't even aware CP was compatible with Flexicontent.
We just gave it a try to be sure: yes, it works! (because Flexicontent's wise developers decided to write data into the standard content table)
Anyway, if you want the CPTags button to show up under the editor, a little tweaking is required:
Edit file plugins/editors-xtd/cptags/cptags.php
change lines 50-51 from
Code:
$option = JRequest::getCmd('option','');
$ces = CpContentElements::getInstance();
to
Code:
$option = JRequest::getCmd('option','');
if($option == 'com_flexicontent') $option = 'com_content';
$ces = CpContentElements::getInstance();
