diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/field/ParameterField.java b/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/field/ParameterField.java
index ea11b977069ee2ebd607f2abcf78c68d8911330d..ade418580035cdb49c74969a6fdff355b063b6d3 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/field/ParameterField.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/field/ParameterField.java
@@ -49,7 +49,7 @@ import ch.systemsx.cisd.openbis.generic.shared.basic.dto.ParameterWithValue;
 public class ParameterField extends TriggerField<ModelData> implements IParameterField
 {
 
-    private static String PARAMETER_NAME_SEPARATOR = "::";
+    public static String PARAMETER_METADATA_SEPARATOR = "::";
 
     private static String ENUM_LIST_EXPRESSION_PREFIX = "list=";
 
@@ -61,7 +61,7 @@ public class ParameterField extends TriggerField<ModelData> implements IParamete
             String initialValueOrNull, IDelegatedAction onValueChangeAction,
             IParameterValuesLoader loaderOrNull)
     {
-        String[] split = parameterName.split(PARAMETER_NAME_SEPARATOR);
+        String[] split = parameterName.split(PARAMETER_METADATA_SEPARATOR);
         if (split.length == 2)
         {
             final String namePart = split[0];
@@ -111,10 +111,10 @@ public class ParameterField extends TriggerField<ModelData> implements IParamete
         setToolTip(parameterName);
         setFieldLabel(parameterName); // used in custom query testing dialog
         setTriggerStyle("x-form-clear-trigger");
-        setWidth(100);
-        setAllowBlank(false);
+        FieldUtil.setMandatoryFlag(this, true);
         setAutoValidate(true);
         setValidateOnBlur(true);
+        setWidth(100);
     }
 
     public ParameterWithValue getParameterWithValue()
@@ -153,8 +153,6 @@ public class ParameterField extends TriggerField<ModelData> implements IParamete
             DropDownList<ParameterValueModel, ParameterValue> implements IParameterField
     {
 
-        private static final String CHOOSE_MSG = "Choose...";
-
         private static final String VALUE_NOT_IN_LIST_MSG = "Value not in the list";
 
         private static final String EMPTY_MSG = "- No values found -";
@@ -199,7 +197,7 @@ public class ParameterField extends TriggerField<ModelData> implements IParamete
                 String queryExpressionOrNull, List<ParameterValue> valuesOrNull,
                 String initialValueOrNull, final IDelegatedAction onValueChangeAction)
         {
-            super(idSuffix, ModelDataPropertyNames.CODE, parameterName, CHOOSE_MSG, EMPTY_MSG,
+            super(idSuffix, ModelDataPropertyNames.CODE, parameterName, parameterName, EMPTY_MSG,
                     VALUE_NOT_IN_LIST_MSG, true, viewContextOrNull, valuesOrNull == null);
             this.parameterName = parameterName;
             this.queryExpressionOrNull = queryExpressionOrNull;
@@ -215,6 +213,7 @@ public class ParameterField extends TriggerField<ModelData> implements IParamete
                     ModelDataPropertyNames.TOOLTIP));
             FieldUtil.setMandatoryFlag(this, true);
             setAllowValueNotFromList(true);
+            setToolTip(parameterName);
             setWidth(100);
 
             addSelectionChangedListener(new SelectionChangedListener<ParameterValueModel>()
diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/plugin/query/client/web/client/application/module/RunCannedQueryToolbar.java b/openbis/source/java/ch/systemsx/cisd/openbis/plugin/query/client/web/client/application/module/RunCannedQueryToolbar.java
index 7d6a6f51cc5dfa9a6dddc34af14b65d7f0a9ffd7..cb303c56b750f8b2c62aa9da2f4156b3c1ba2865 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/plugin/query/client/web/client/application/module/RunCannedQueryToolbar.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/plugin/query/client/web/client/application/module/RunCannedQueryToolbar.java
@@ -187,15 +187,16 @@ public class RunCannedQueryToolbar extends AbstractQueryProviderToolbar
                             queryExpression, listParameterValuesCallback);
                 }
             };
-        for (String parameter : query.getParameters())
+        for (String parameterName : query.getParameters())
         {
-            final QueryParameterValue initialValueOrNull = tryGetInitialValue(parameter);
+            final QueryParameterValue initialValueOrNull =
+                    tryGetInitialValue(stripMetadata(parameterName));
             if (initialValueOrNull != null && initialValueOrNull.isFixed())
             {
-                addInitialBinding(parameter, initialValueOrNull.getValue());
+                addInitialBinding(parameterName, initialValueOrNull.getValue());
             } else
             {
-                addParameterField(ParameterField.create(viewContext, parameter,
+                addParameterField(ParameterField.create(viewContext, parameterName,
                         initialValueOrNull == null ? null : initialValueOrNull.getValue(),
                         updateExecuteButtonAction, parameterValuesloader));
             }
@@ -204,7 +205,6 @@ public class RunCannedQueryToolbar extends AbstractQueryProviderToolbar
 
     private void addInitialBinding(String parameter, String value)
     {
-
         initialFixedParameters.put(parameter, value);
     }
 
@@ -304,4 +304,12 @@ public class RunCannedQueryToolbar extends AbstractQueryProviderToolbar
         querySelectionWidget.update(observedModifications);
     }
 
+    // helpers
+
+    private static String stripMetadata(String parameterName)
+    {
+        int indexOfSeparator = parameterName.indexOf(ParameterField.PARAMETER_METADATA_SEPARATOR);
+        return indexOfSeparator > -1 ? parameterName.substring(0, indexOfSeparator) : parameterName;
+    }
+
 }