Missing the path to the custom jdom fields in config.xml
file COMPONENT\admin\config.xml:
It is:
<fieldset name="configuration"
label="COMPONENT_CONFIG_COMPONENT_CONFIGURATION"
description="COMPONENT_CONFIG_COMPONENT_CONFIGURATION_1">
it should be:
<fieldset name="configuration"
label="COMPONENT_CONFIG_COMPONENT_CONFIGURATION"
addfieldpath="/administrator/components/com_component/models/fields"
description="COMPONENT_CONFIG_COMPONENT_CONFIGURATION_1">
otherwise the type="cktext" cannot be loaded.
It still works because joomla by default call the text input type when it doesn't find the type declared, but if you add other JDOM fields, they will not work.