diff --git a/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/CreateDatasetForm.java b/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/CreateDatasetForm.java
index b3ed466..90f65ba 100644
--- a/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/CreateDatasetForm.java
+++ b/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/CreateDatasetForm.java
@@ -130,6 +130,9 @@ public class CreateDatasetForm extends Composite{
 	@UiField Icon infoIconTags;
 	@UiField FocusPanel focusPanelTags;
 	@UiField Popover popoverTags;
+	@UiField Icon infoIconLicenses;
+	@UiField FocusPanel focusPanelLicenses;
+	@UiField Popover popoverLicenses;
 	@UiField Icon infoIconVisibility;
 	@UiField FocusPanel focusPanelVisibility;
 	@UiField Popover popoverVisibility;
@@ -808,6 +811,16 @@ public class CreateDatasetForm extends Composite{
 				popoverTags,
 				focusPanelTags
 				);
+		
+		// licenses
+		preparePopupPanelAndPopover(
+				InfoIconsLabels.LICENSES_INFO_ID_POPUP,
+				InfoIconsLabels.LICENSES_INFO_TEXT,
+				InfoIconsLabels.LICENSES_INFO_CAPTION,
+				infoIconLicenses,
+				popoverLicenses,
+				focusPanelLicenses
+				);
 
 		// visibility
 		preparePopupPanelAndPopover(
@@ -899,8 +912,10 @@ public class CreateDatasetForm extends Composite{
 
 		for (MetaDataFieldSkeleton field : listOfMetadataFields) {
 
-			if(!field.isFieldValueValid())
-				return field.getFieldName() + " is not valid";
+			String error = field.isFieldValueValid();
+			if(error != null){
+				return field.getFieldName() + " is not valid. Suggestion: " + error;
+			}
 		}
 
 		return null;
@@ -957,7 +972,7 @@ public class CreateDatasetForm extends Composite{
 			}
 		};
 
-		t.schedule(4000);
+		t.schedule(10000);
 	}
 
 	/**
diff --git a/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/CreateDatasetForm.ui.xml b/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/CreateDatasetForm.ui.xml
index 95f0de2..f6e1a1f 100644
--- a/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/CreateDatasetForm.ui.xml
+++ b/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/CreateDatasetForm.ui.xml
@@ -109,6 +109,14 @@
 						<b:ListBox b:id="licenses" title="Product license"
 							width="91%" ui:field="licenseListbox">
 						</b:ListBox>
+						<span style="float:right; width:5%; color: #aaaaaa;">
+							<b:Popover ui:field="popoverLicenses" html="true"
+								animation="true" placement="LEFT">
+								<g:FocusPanel ui:field="focusPanelLicenses">
+									<b:Icon type="INFO_SIGN" size="TWO_TIMES" ui:field="infoIconLicenses" />
+								</g:FocusPanel>
+							</b:Popover>
+						</span>
 					</b:Controls>
 				</b:ControlGroup>
 
diff --git a/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/MetaDataFieldSkeleton.java b/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/MetaDataFieldSkeleton.java
index b5193cb..2f44ec2 100644
--- a/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/MetaDataFieldSkeleton.java
+++ b/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/MetaDataFieldSkeleton.java
@@ -213,32 +213,29 @@ public class MetaDataFieldSkeleton extends Composite{
 
 	/**
 	 * Check if this field has a valid values
-	 * @return
+	 * @return a string with the occurred error on error, null otherwise
 	 */
-	public boolean isFieldValueValid(){
-
-		GWT.log("Validator is " + field.getValidator());
-		GWT.log("Is mandatory? " + field.getMandatory());
+	public String isFieldValueValid(){
 
 		if(field.getMandatory()){
 			if(holder.getClass().equals(TextBox.class)){
 
 				if(!getFieldCurrentValue().isEmpty())
 					if(field.getValidator() == null || field.getValidator().isEmpty())
-						return true;
-					else return checkValidator(holder, field);
+						return null;
+					else return checkValidator(holder, field) ? null : " the inserted value has a wrong format";
 				else
-					return false;
+					return " a mandatory attribute cannot be empty";
 
 			}else
-				return true;
+				return null;
 
 		}else{
 
 			if(holder.getClass().equals(TextBox.class) && getFieldCurrentValue().isEmpty())
-				return true;
+				return null;
 
-			return checkValidator(holder, field);
+			return checkValidator(holder, field) ? null : " please select a different value for this field";
 
 		}
 	}
diff --git a/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/utils/InfoIconsLabels.java b/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/utils/InfoIconsLabels.java
index 0027e45..451921a 100644
--- a/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/utils/InfoIconsLabels.java
+++ b/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/utils/InfoIconsLabels.java
@@ -13,6 +13,11 @@ public class InfoIconsLabels {
 			+ "product and by means of them it can be retrieved. A tag can contain only alphanumeric characters. "
 			+ "If the tag is composed by a single word it must have a size of at least two characters."
 			+ "Examples of good tags: \"This is a sample tag\", \"tagY\". Example of bad tag: \"c\".";
+	
+	// LICENSES
+	public static final String LICENSES_INFO_ID_POPUP = "licenses-popup-panel-info";
+	public static final String LICENSES_INFO_CAPTION = "Licenses";
+	public static final String LICENSES_INFO_TEXT = "License definitions and additional information can be found at <a href=\"http://opendefinition.org/licenses/\" target=\"_blank\">opendefinition.org</a>";
 
 	// VISIBILITY
 	public static final String VISIBILITY_INFO_ID_POPUP = "visibility-popup-panel-info";