[2453] Add Show/Hide section in the group palette

CHANGELOG.adoc

@@ -73,6 +73,7 @@ This removes Rollup warnings about missing global names for externalized peer de
 - [releng] Reduce the log of the frontend tasks `format-lint` and `build-dev` by default to make tasks such as `build` or `start` less verbose.
 - [cleanup] Use only one border node description provider for all item border nodes.
 - https://github.com/eclipse-syson/syson/issues/2452[#2352] [diagram] Decouple SysON tools from Sirius Web's DefaultToolsFactory: SysON now defines its own `DiagramDefaultToolsFactory` providing show/hide tools.
+- https://github.com/eclipse-syson/syson/issues/2453[#2453] [diagrams] Add the Show/Hide section and associated tools to the group palette.
 
 === New features
 

backend/views/syson-diagram-common-view/src/main/java/org/eclipse/syson/diagram/common/view/DiagramDefaultGroupToolsFactory.java

@@ -0,0 +1,97 @@
+/*******************************************************************************
+ * Copyright (c) 2026 Obeo.
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Obeo - initial API and implementation
+ *******************************************************************************/
+
+package org.eclipse.syson.diagram.common.view;
+
+import org.eclipse.sirius.components.view.ChangeContext;
+import org.eclipse.sirius.components.view.ViewFactory;
+import org.eclipse.sirius.components.view.diagram.DiagramFactory;
+import org.eclipse.sirius.components.view.diagram.NodeTool;
+import org.eclipse.sirius.components.view.diagram.NodeToolSection;
+
+/**
+ * Factory to create generic group tool descriptions which invoke the default/canonical behaviors.
+ *
+ * @author tgiraudet
+ */
+public class DiagramDefaultGroupToolsFactory {
+
+    private static final String HAS_CHILDREN_EXPRESSION = "aql:selectedNodes.getChildNodes()->notEmpty() or selectedNodes.getBorderNodes()->notEmpty()";
+
+    private static final String HAS_HIDDEN_CHILDREN_EXPRESSION = "aql:selectedNodes.getChildNodes()->union(selectedNodes.getBorderNodes())->select(n | n.isHidden())->notEmpty()";
+
+    public NodeToolSection createDefaultHideRevealNodeToolSection() {
+        NodeToolSection nodeToolSection = DiagramFactory.eINSTANCE.createNodeToolSection();
+        nodeToolSection.setName("Show/Hide");
+        nodeToolSection.getNodeTools().add(this.createDefaultHideNodeTool());
+        nodeToolSection.getNodeTools().add(this.createDefaultHideAllChildrenNodeTool());
+        nodeToolSection.getNodeTools().add(this.createDefaultRevealAllChildrenNodeTool());
+        nodeToolSection.getNodeTools().add(this.createDefaultResetAllChildrenVisibilityModifiersNodeTool());
+        nodeToolSection.getNodeTools().add(this.createDefaultRevealChildrenWithValueNodeTool());
+        return nodeToolSection;
+    }
+
+    public NodeTool createDefaultHideNodeTool() {
+        NodeTool newNodeTool = DiagramFactory.eINSTANCE.createNodeTool();
+        newNodeTool.setName("Hide");
+        ChangeContext body = ViewFactory.eINSTANCE.createChangeContext();
+        body.setExpression("aql:diagramServices.hide(selectedNodes)");
+        newNodeTool.getBody().add(body);
+        newNodeTool.setIconURLsExpression("aql:'/icons/full/obj16/HideTool.svg'");
+        return newNodeTool;
+    }
+
+    public NodeTool createDefaultHideAllChildrenNodeTool() {
+        NodeTool newNodeTool = DiagramFactory.eINSTANCE.createNodeTool();
+        newNodeTool.setName("Hide all content");
+        ChangeContext body = ViewFactory.eINSTANCE.createChangeContext();
+        body.setExpression("aql:diagramServices.hide(selectedNodes.getChildNodes()->union(selectedNodes.getBorderNodes()))");
+        newNodeTool.getBody().add(body);
+        newNodeTool.setIconURLsExpression("aql:'/icons/full/obj16/HideTool.svg'");
+        newNodeTool.setPreconditionExpression("aql:selectedNodes.getChildNodes()->notEmpty() or selectedNodes.getBorderNodes()->notEmpty()");
+        return newNodeTool;
+    }
+
+    public NodeTool createDefaultRevealAllChildrenNodeTool() {
+        NodeTool newNodeTool = DiagramFactory.eINSTANCE.createNodeTool();
+        newNodeTool.setName("Show all content");
+        ChangeContext body = ViewFactory.eINSTANCE.createChangeContext();
+        body.setExpression("aql:diagramServices.reveal(selectedNodes.getChildNodes()->union(selectedNodes.getBorderNodes()))");
+        newNodeTool.getBody().add(body);
+        newNodeTool.setIconURLsExpression("aql:'/icons/full/obj16/ShowTool.svg'");
+        newNodeTool.setPreconditionExpression("aql:selectedNodes.getChildNodes()->union(selectedNodes.getBorderNodes())->select(n | n.isHidden())->notEmpty()");
+        return newNodeTool;
+    }
+
+    public NodeTool createDefaultResetAllChildrenVisibilityModifiersNodeTool() {
+        NodeTool newNodeTool = DiagramFactory.eINSTANCE.createNodeTool();
+        newNodeTool.setName("Reset content");
+        ChangeContext body = ViewFactory.eINSTANCE.createChangeContext();
+        body.setExpression("aql:diagramServices.resetViewModifiers(selectedNodes.getChildNodes()->union(selectedNodes.getBorderNodes()))");
+        newNodeTool.getBody().add(body);
+        newNodeTool.setIconURLsExpression("aql:'/icons/full/obj16/ShowTool.svg'");
+        newNodeTool.setPreconditionExpression(HAS_CHILDREN_EXPRESSION);
+        return newNodeTool;
+    }
+
+    public NodeTool createDefaultRevealChildrenWithValueNodeTool() {
+        NodeTool newNodeTool = DiagramFactory.eINSTANCE.createNodeTool();
+        newNodeTool.setName("Show valued content");
+        ChangeContext body = ViewFactory.eINSTANCE.createChangeContext();
+        body.setExpression("aql:diagramServices.reveal(selectedNodes.getChildNodes()->union(selectedNodes.getBorderNodes())->select(n | n.getChildNodes()->notEmpty() or n.getBorderNodes()->notEmpty()))");
+        newNodeTool.getBody().add(body);
+        newNodeTool.setIconURLsExpression("aql:'/icons/full/obj16/ShowTool.svg'");
+        newNodeTool.setPreconditionExpression(HAS_HIDDEN_CHILDREN_EXPRESSION);
+        return newNodeTool;
+    }
+}

backend/views/syson-standard-diagrams-view/src/main/java/org/eclipse/syson/standard/diagrams/view/SDVDiagramDescriptionProvider.java

@@ -42,6 +42,7 @@
 import org.eclipse.sirius.components.view.diagram.NodeTool;
 import org.eclipse.sirius.components.view.diagram.ToolSection;
 import org.eclipse.sirius.components.view.emf.diagram.ViewDiagramDescriptionConverter;
+import org.eclipse.syson.diagram.common.view.DiagramDefaultGroupToolsFactory;
 import org.eclipse.syson.diagram.common.view.ViewDiagramElementFinder;
 import org.eclipse.syson.diagram.common.view.edges.AnnotationEdgeDescriptionProvider;
 import org.eclipse.syson.diagram.common.view.nodes.ActionFlowCompartmentNodeDescriptionProvider;
@@ -431,6 +432,7 @@ private List<ToolSection> createGroupToolSections() {
                 .build();
         groupToolSections.add(viewAsToolSection);
         groupToolSections.add(this.toolDescriptionService.relatedElementsGroupToolSection());
+        groupToolSections.add(new DiagramDefaultGroupToolsFactory().createDefaultHideRevealNodeToolSection());
         return groupToolSections;
     }
 

doc/content/modules/user-manual/pages/release-notes/2026.9.0.adoc

@@ -149,6 +149,11 @@ image::release-notes-hierarchical-requirements-table-view.png[Hierarchical requi
 +
 image::release-notes-hierarchical-requirements-table-view-create-nested-requirement.png[New sub-requirement in row action menu, width=90%,height=90%]
 
+** When selecting multiple graphical nodes, the group palette now displays the _Show/Hide_ section just like the single selection palette.
+The associated tools are the same ones: _Hide_; _Hide all content_; _Show all content_; _Reset content_; _Show valued content_.
++
+image::release-notes-show-hide-section-group-palette.png[New Show/Hide section in group palette, width=90%,height=90%]
+
 == Technical details
 
 * For technical details on this {product} release, including breaking changes, please refer to the https://github.com/eclipse-syson/syson/blob/main/CHANGELOG.adoc[changelog].

doc/content/modules/user-manual/partials/manage-group-elements.adoc

@@ -11,10 +11,12 @@ image::manage-group-element-toolbar.png[Group element toolbar]
 User can still used basic tools such as :
 
 * Hide elements,
+* Hide all their content,
+* Show their valued content,
 * Fade elements,
 * Pin elements.
 
-A new tool section appears in this toolbar.
+A layout tool section appears in this toolbar.
 Many tools acting on selected elements layout can be found in this tool section :
 
 * Align left,