[Lazarus] Is this bug ? or how to do?

[FreeMan]

Hello,
I'm writeing my exlookup component, I add 2 datasource and 3 field. Like 
a dblookupcombobox.
my component's properties:
     FDataField : TFieldDataLink;
     FListField : TFieldDataLink;
     FKeyField  : TFieldDataLink;

On Objectinspector, property editor work just for, if Property name is 
"DataField" my idea is propertyeditor check property 
name('datafield')not classname or type "TFieldDataLink" . I mean 
fieldlist combobox work on OI just if propertyname is "datafield". 
second or third field name not listing, just string edit, not combobox. 
this is same on "TDBLookupComboBox".
Is this bug or I have to use some code for this.
Thank you.