diff --git a/APPL/Shared/kenmerk_common.inc b/APPL/Shared/kenmerk_common.inc
index 30518949f6..ee3c1edd5d 100644
--- a/APPL/Shared/kenmerk_common.inc
+++ b/APPL/Shared/kenmerk_common.inc
@@ -569,8 +569,10 @@ function listKenmerk(sql, module, key, props)
                     + " onBlur='checkKenmerk(this, true,\"" + ktype + "\"," + klen + "," + kdec + "," + kmin + "," + kmax + ")'"
                     + " class='fldflexC50 "
                       + (required ? required_class : "")
+                      + (isExpression? " expression " : "")
                       + "'"
                     + (required ? " required='required' " : "")
+                    + (isExpression ? " readonly " : "")
                     + " rows=3 "
                     + " maxlength='"+klen+"'"
                     + " name='" + nameprefix + idCounter + "val' id='" + nameprefix + idCounter + "val' "
@@ -604,8 +606,10 @@ function listKenmerk(sql, module, key, props)
                     + " class='"
                       + (kenmerk_search ? "fldSflexC " : "fldflexC ")
                       + (required ? required_class : "")
+                      + (isExpression? " expression " : "")
                       + "'"
                     + (required ? " required='required' " : "")
+                    + (isExpression ? " readonly " : "")
                     //+ " placeholder='"+val_label+"'"
                     + " value='" + safe.htmlattr(val) + "'"
                     + " maxlength='" + klen + "'"