diff --git a/sources/Forms/Block/AbstractTypeFormBlock.php b/sources/Forms/Block/AbstractTypeFormBlock.php
index 9e85e3686..9d1a7516b 100644
--- a/sources/Forms/Block/AbstractTypeFormBlock.php
+++ b/sources/Forms/Block/AbstractTypeFormBlock.php
@@ -22,8 +22,8 @@ use Combodo\iTop\Forms\Register\RegisterException;
 abstract class AbstractTypeFormBlock extends AbstractFormBlock
 {
 	// Inputs
-	public const INPUT_VISIBLE = 'visible';
-	public const INPUT_ENABLE = 'enable';
+	public const INPUT_VISIBLE = 'input_visible';
+	public const INPUT_ENABLE = 'input_enable';
 
 	/** @var bool flag indicating the form insertion */
 	private bool $bIsAddedToForm = false;
diff --git a/sources/Forms/Block/Base/CheckboxFormBlock.php b/sources/Forms/Block/Base/CheckboxFormBlock.php
index ea24705a7..6554de91e 100644
--- a/sources/Forms/Block/Base/CheckboxFormBlock.php
+++ b/sources/Forms/Block/Base/CheckboxFormBlock.php
@@ -24,7 +24,7 @@ use Symfony\Component\Form\Extension\Core\Type\CheckboxType;
 class CheckboxFormBlock extends AbstractTypeFormBlock
 {
 	// outputs
-	public const OUTPUT_CHECKED = 'checked';
+	public const OUTPUT_CHECKED = 'output_checked';
 
 	/** @inheritdoc */
 	public function GetFormType(): string
diff --git a/sources/Forms/Block/Base/ChoiceFormBlock.php b/sources/Forms/Block/Base/ChoiceFormBlock.php
index 8c05f0a50..aca89dac5 100644
--- a/sources/Forms/Block/Base/ChoiceFormBlock.php
+++ b/sources/Forms/Block/Base/ChoiceFormBlock.php
@@ -23,8 +23,8 @@ use Combodo\iTop\Forms\Register\IORegister;
 class ChoiceFormBlock extends AbstractTypeFormBlock
 {
 	// Outputs
-	public const OUTPUT_LABEL = 'label';
-	public const OUTPUT_VALUE = 'value';
+	public const OUTPUT_LABEL = 'output_label';
+	public const OUTPUT_VALUE = 'output_value';
 
 	/** @inheritdoc */
 	public function GetFormType(): string
diff --git a/sources/Forms/Block/Base/CollectionBlock.php b/sources/Forms/Block/Base/CollectionBlock.php
index e7c1e772e..f1653eff6 100644
--- a/sources/Forms/Block/Base/CollectionBlock.php
+++ b/sources/Forms/Block/Base/CollectionBlock.php
@@ -23,7 +23,7 @@ use Combodo\iTop\Forms\Register\RegisterException;
 class CollectionBlock extends AbstractTypeFormBlock
 {
 	// Inputs
-	public const INPUT_CLASS_NAME = 'class_name';
+	public const INPUT_CLASS_NAME = 'input_class_name';
 
 	/** @var FormBlock block */
 	protected AbstractTypeFormBlock $oPrototypeBlock;
diff --git a/sources/Forms/Block/Base/NumberFormBlock.php b/sources/Forms/Block/Base/NumberFormBlock.php
index a7ac15a7b..4518d30a3 100644
--- a/sources/Forms/Block/Base/NumberFormBlock.php
+++ b/sources/Forms/Block/Base/NumberFormBlock.php
@@ -22,7 +22,7 @@ use Symfony\Component\Form\Extension\Core\Type\NumberType;
 class NumberFormBlock extends AbstractTypeFormBlock
 {
 	// Outputs
-	public const OUTPUT_NUMBER = "number";
+	public const OUTPUT_NUMBER = "output_number";
 
 	/** @inheritdoc */
 	public function GetFormType(): string
diff --git a/sources/Forms/Block/Base/TextFormBlock.php b/sources/Forms/Block/Base/TextFormBlock.php
index 5a6b74606..741571e7c 100644
--- a/sources/Forms/Block/Base/TextFormBlock.php
+++ b/sources/Forms/Block/Base/TextFormBlock.php
@@ -22,7 +22,7 @@ use Symfony\Component\Form\Extension\Core\Type\TextType;
 class TextFormBlock extends AbstractTypeFormBlock
 {
 	// Outputs
-	public const OUTPUT_TEXT = "text";
+	public const OUTPUT_TEXT = "output_text";
 
 	/** @inheritdoc */
 	public function GetFormType(): string
diff --git a/sources/Forms/Block/DataModel/AttributeChoiceFormBlock.php b/sources/Forms/Block/DataModel/AttributeChoiceFormBlock.php
index 39554afe6..a78419623 100644
--- a/sources/Forms/Block/DataModel/AttributeChoiceFormBlock.php
+++ b/sources/Forms/Block/DataModel/AttributeChoiceFormBlock.php
@@ -28,16 +28,17 @@ use utils;
 class AttributeChoiceFormBlock extends ChoiceFormBlock
 {
 	// inputs
-	public const INPUT_CLASS_NAME = 'class_name';
+	public const INPUT_CLASS_NAME = 'input_class_name';
 
 	// outputs
-	public const OUTPUT_ATTRIBUTE = 'attribute';
+	public const OUTPUT_ATTRIBUTE = 'output_attribute';
 
 	/** @inheritdoc */
 	protected function RegisterOptions(OptionsRegister $oOptionsRegister): void
 	{
 		parent::RegisterOptions($oOptionsRegister);
 		$oOptionsRegister->SetOption('placeholder', 'Select an attribute...');
+		$oOptionsRegister->SetOption('category', '', false);
 	}
 
 	/** @inheritdoc */
diff --git a/sources/Forms/Block/DataModel/AttributeValueChoiceFormBlock.php b/sources/Forms/Block/DataModel/AttributeValueChoiceFormBlock.php
index 2a1b6d2e2..fe2811758 100644
--- a/sources/Forms/Block/DataModel/AttributeValueChoiceFormBlock.php
+++ b/sources/Forms/Block/DataModel/AttributeValueChoiceFormBlock.php
@@ -25,8 +25,8 @@ use Exception;
 class AttributeValueChoiceFormBlock extends ChoiceFormBlock
 {
 	// inputs
-	public const INPUT_CLASS_NAME = 'class_name';
-	public const INPUT_ATTRIBUTE  = 'attribute';
+	public const INPUT_CLASS_NAME = 'input_class_name';
+	public const INPUT_ATTRIBUTE  = 'input_attribute';
 
 	/** @inheritdoc */
 	protected function RegisterOptions(OptionsRegister $oOptionsRegister): void
diff --git a/sources/Forms/Block/DataModel/OqlFormBlock.php b/sources/Forms/Block/DataModel/OqlFormBlock.php
index dc4c34525..7412cb8a4 100644
--- a/sources/Forms/Block/DataModel/OqlFormBlock.php
+++ b/sources/Forms/Block/DataModel/OqlFormBlock.php
@@ -24,7 +24,7 @@ use Combodo\iTop\Forms\Register\OptionsRegister;
 class OqlFormBlock extends TextAreaFormBlock
 {
 	// outputs
-	public const OUTPUT_SELECTED_CLASS = 'selected_class';
+	public const OUTPUT_SELECTED_CLASS = 'output_selected_class';
 
 	/** @inheritdoc */
 	public function GetFormType(): string
diff --git a/sources/Forms/Block/Expression/BooleanExpressionFormBlock.php b/sources/Forms/Block/Expression/BooleanExpressionFormBlock.php
index 590bdfaed..df8ff0b36 100644
--- a/sources/Forms/Block/Expression/BooleanExpressionFormBlock.php
+++ b/sources/Forms/Block/Expression/BooleanExpressionFormBlock.php
@@ -21,8 +21,8 @@ use Combodo\iTop\Forms\Register\IORegister;
 class BooleanExpressionFormBlock extends AbstractExpressionFormBlock
 {
 	// Outputs
-	public const OUTPUT_RESULT = "result";
-	public const OUTPUT_NOT_RESULT = "not_result";
+	public const OUTPUT_RESULT = "output_result";
+	public const OUTPUT_NOT_RESULT = "output_not_result";
 
 	/** @inheritdoc */
 	protected function RegisterIO(IORegister $oIORegister): void
diff --git a/sources/Forms/Block/Expression/NumberExpressionFormBlock.php b/sources/Forms/Block/Expression/NumberExpressionFormBlock.php
index 038003a18..ad50dcf45 100644
--- a/sources/Forms/Block/Expression/NumberExpressionFormBlock.php
+++ b/sources/Forms/Block/Expression/NumberExpressionFormBlock.php
@@ -21,7 +21,7 @@ use Combodo\iTop\Forms\Register\IORegister;
 class NumberExpressionFormBlock extends AbstractExpressionFormBlock
 {
 	// Outputs
-	public const OUTPUT_RESULT = "result";
+	public const OUTPUT_RESULT = "output_result";
 
 	/** @inheritdoc */
 	protected function RegisterIO(IORegister $oIORegister): void