diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/field/CodeFieldWithGenerator.java b/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/field/CodeFieldWithGenerator.java
index 77d64dde2582fcae56343711d2934c4b4f645d96..ee533b0dbb0f54a0553ab7bebc63a7291325cc67 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/field/CodeFieldWithGenerator.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/field/CodeFieldWithGenerator.java
@@ -57,6 +57,16 @@ public class CodeFieldWithGenerator extends CodeField
         }
     }
 
+    @Override
+    public void setHideTrigger(boolean hideTrigger)
+    {
+        super.setHideTrigger(hideTrigger);
+        if (hideTrigger == true)
+        {
+            setTitle("");
+        }
+    }
+
     @Override
     public void reset()
     {
diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/plugin/generic/client/web/client/application/AbstractGenericEntityRegistrationForm.java b/openbis/source/java/ch/systemsx/cisd/openbis/plugin/generic/client/web/client/application/AbstractGenericEntityRegistrationForm.java
index 9282dfb8505f63e91b1107b38fcf3b1e9a0cfacc..ec16c67b02d922c84f29d42a7446263b01a64d84 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/plugin/generic/client/web/client/application/AbstractGenericEntityRegistrationForm.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/plugin/generic/client/web/client/application/AbstractGenericEntityRegistrationForm.java
@@ -182,6 +182,12 @@ public abstract class AbstractGenericEntityRegistrationForm<T extends EntityType
         boolean codeReadonly = techIdOrNull != null || isAutoGenerateCode();
         codeField.setReadOnly(codeReadonly);
         codeField.setHideTrigger(codeReadonly);
+        if (techIdOrNull != null)
+        {
+            // we don't want to validate code during edition
+            // (contained sample code has ':' inside and it is invalid)
+            codeField.disable();
+        }
     }
 
     /**