[TYPO3-dev] Using ###REC_FIELD_[fieldname]### marker in flexforms

[Tadeusz Dracz]

Hello, 
I try to use the ###REC_FIELD_[fieldname]### marker in a FlexForm definition
for my content plugin backend editor. However it never is replaced by the
field's value. Am I doing some elementary mistake or it's just not possible?
(I'm trying to display groups for selection that come only from a specified
folder - I cannot use ###STORAGE_PID### here, because it is already used for
a different purpose). Below is my FlexForm partial definition. 

Thank you in advance, 
Tadeusz 

<T3DataStructure>
	<meta>
		<langDisable>1</langDisable>
	</meta>
  <ROOT>
    <type>array</type>
    <el>     
	  <groupsStoragePage>
      	<TCEforms>
	
<label>LLL:EXT:myextension/locallang_db.xml:groups.page</label>
			<onChange>reload</onChange>
      		<config>
	      		<type>input</type>				
	      		<eval>required,int</eval>
      		</config>
      	</TCEforms>
      </groupsStoragePage>
	  <field_groups>
			<TCEforms>
				<label>LLL:EXT: myextension
/locallang_db.xml:groups.groups</label>
	
<displayCond>FIELD:groupsStoragePage:REQ:true</displayCond>
				<config>
					<type>select</type>
				<items></items>
				<foreign_table>fe_groups</foreign_table>
				<foreign_table_where>	
					AND fe_groups.pid
=###REC_FIELD_groupsStoragePage###
					ORDER BY fe_groups.title
				</foreign_table_where>
				<size>10</size>
				<minitems>1</minitems>
				<maxitems>50</maxitems>
				</config>
			</TCEforms>
	  </field_groups>	
.......