diff --git a/content/student/studentdetailoverlay.xul.php b/content/student/studentdetailoverlay.xul.php
index 6e777dcad..34aab7dea 100644
--- a/content/student/studentdetailoverlay.xul.php
+++ b/content/student/studentdetailoverlay.xul.php
@@ -97,7 +97,7 @@ echo '<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>';
       						<label value="SVNR" control="student-detail-textbox-svnr"/>
       						<hbox><textbox id="student-detail-textbox-svnr" disabled="true" maxlength="10" size="10"/></hbox>
       						<label value="Ersatzkennzeichen" control="student-detail-textbox-ersatzkennzeichen"/>
-      						<hbox><textbox id="student-detail-textbox-ersatzkennzeichen" disabled="true" maxlength="10" size="10"/></hbox>
+      						<hbox><textbox id="student-detail-textbox-ersatzkennzeichen" disabled="true" maxlength="10" size="15"/></hbox>
       						<label value="Geburtszeit" control="student-detail-textbox-geburtszeit"/>
       						<hbox><textbox id="student-detail-textbox-geburtszeit" disabled="true" maxlength="5" size="5" tooltiptext="Format: hh:mm Beispiel: 10:30"/></hbox>
     					</row>