N°803 - Allow display & edition of attributes on n:n relations on Portal

- Remove input when object is in view mode
- Improve form errors handling
- Prevent row selection when clicking input 
- Attach date time picker to table instead of input to prevent popup truncating (popup will be visible but not aligned on the input)

core/attributedef.class.inc.php

@@ -9,6 +9,7 @@ use Combodo\iTop\Application\UI\Links\Set\BlockLinkSetDisplayAsProperty;
 use Combodo\iTop\Form\Field\LabelField;
 use Combodo\iTop\Form\Field\TextAreaField;
 use Combodo\iTop\Form\Form;
+use Combodo\iTop\Form\Validator\LinkedSetValidator;
 use Combodo\iTop\Form\Validator\NotEmptyExtKeyValidator;
 use Combodo\iTop\Form\Validator\Validator;
 use Combodo\iTop\Renderer\BlockRenderer;
@@ -2446,6 +2447,8 @@ class AttributeLinkedSet extends AttributeDefinition
 			$oFormField->SetLnkAttributesToDisplay($aLnkAttributesToDisplay);
 		}
 
+		$oFormField->AddValidator(new LinkedSetValidator());
+
 		parent::MakeFormField($oObject, $oFormField);
 
 		return $oFormField;