Index: typo3/sysext/rtehtmlarea/class.tx_rtehtmlarea_base.php
===================================================================
--- typo3/sysext/rtehtmlarea/class.tx_rtehtmlarea_base.php	(revision 8945)
+++ typo3/sysext/rtehtmlarea/class.tx_rtehtmlarea_base.php	(working copy)
@@ -1370,9 +1370,8 @@
 	 *
 	 * @return boolean
 	 */
-
 	function is_FE() {
-		return is_object($GLOBALS['TSFE']) && !$this->isFrontendEditActive();
+		return is_object($GLOBALS['TSFE']) && !$this->isFrontendEditActive() && TYPO3_MODE == 'FE';
 	}
 
 	/**